Key to Violaceae of Northeastern North America by Ballard, Kartesz, and Nishino (2023)


Key and its associated effective range illustration from A taxonomic treatment of the violets (Violaceae) of the northeastern United States and adjacent Canada by Harvey E. Ballard Jr, John T. Kartesz, and Misako Nishino, published in The Journal of the Torrey Botanical Society, 150(1):3-266 (2023). https://doi.org/10.3159/TORREY-D-22-00029.1


Keys to Violaceae

Key A. Genera

1a. Plant acaulescent or caulescent, if caulescent then leafy nodes typically ≤ 8 per stem; leaf blades of many species about as broad as long or broader, base cordate; flowers solitary; peduncle not articulated, bearing a pair of bracteoles; sepals with basal auricles; bottom petal spurred at base, blade distinctly shorter than lateral and upper petals . . . Viola, (Key C)

1b. Plant caulescent, leafy nodes > 10 per stem; leaf blades much longer than broad, base narrowly cuneate; flowers solitary or in few-flowered reduced cymes; peduncle/pedicel articulated, lacking bracteoles; sepals lacking basal auricles; bottom petal saccate at base, blade slightly to greatly exserted beyond lateral and upper petals . . . (2)

2(1)a. Stem unbranched; leaves strictly alternate; leaf blades oblanceolate, entire or with 1–2 irregular coarse teeth on either margin; flowers 1–3 in reduced cymes; corolla uniformly green; bottom petal < 1.3 × as long as others, blade slightly expanded, retuse; capsule 15–23 mm long; seeds 4.5–5.0 × 3.5–4.8 mm, subglobose, tan; native to rich mesic and lowland forests in eastern North America . . . Cubelium concolor (T.F.Forst.) Raf.

2(1)b. Stem branched from base or lower nodes; upper leaves alternate and lower (sub)opposite; leaf blades narrowly linear or linear-lanceolate and entire, or lanceolate or elliptic to rhombic-lanceolate and uniformly crenate-serrate; flowers solitary; corolla white, violet, or greenish to dull yellow tinged with violet, throat yellow; bottom petal > 1.3 × as long as others, blade somewhat to very much expanded, emarginate or broadly rounded; capsule < 10 mm long; seeds < 2 mm broad, flattened, black; one species native to grasslands and desert scrub in Great Plains and North America (not yet recorded from our region), one Latin American species introduced in New Jersey and Georgia . . . Pombalia, (Key B)



Key B. Pombalia

1a. Leaves subtending flowers or fruits much reduced; leaf blades lanceolate or elliptic to rhombic-lanceolate, margins prominently crenate-serrate; apex of bottom petal blade bilobate; native of South America, introduced to New Jersey and Georgia . . . Pombalia parviflora (L.f.) Paula-Souza

1b. Leaves subtending flowers or fruits not reduced; leaf blades narrowly linear to (ob)lanceolate, margins entire; apex of bottom petal broadly rounded; native of grasslands and open xeric sites, southwestern North America and Great Plains (not yet documented in our region, see “Potential Taxa”) . . . Pombalia verticillata (Ortega) Paula-Souza



Key C. Viola

1a. Plant caulescent, producing aerial stems bearing leaves and flowers or capsules at nodes . . . (2)

1b. Plant acaulescent, with leaves and flowers or fruits arising directly from the rootstock (yellow-flowered Viola rotundifolia is acaulescent during spring flowering but produces a stolon-like prostrate stem with 0–1 leaf and 1–3 capsules in summer, and is inserted in Keys C and D) . . . (3)

2(1)a. Corolla yellow or white with a yellow throat (occasionally fading or drying to lavender), ventral surface of petals commonly pink- or purple- to brown-tinged); stipules membranous or partially to wholly herbaceous, margins entire or erose . . . (Key D)

2(1)b. Corolla cream or pale blue or multicolored (violet to purple with orange or yellow) with a yellow throat, or cream-white, pale blue, or violet to purple with a white throat, ventral surface not differently tinged; stipules herbaceous, margins fringed or deeply lobed . . . (Key E)

3(1)a. Plant growing from horizontal stoloniform rhizome, producing surficial or subsurficial leafy stolons especially in summer, rhizome and/or stolons < 3 mm in diameter (rhizome ≥ 3 mm in summer fruiting Viola rotundifolia, stolons lacking in Viola renifolia A.Gray, stolons absent or present and with few leaves in Viola vittata Greene); corolla white, white tinged with violet, or violet, with greenish-white throat and mostly < 1 cm long (in Viola suecica and Viola palustris), or uniformly white or purple and > 1 cm (in Viola odorata) . . . (Key F)

3(1)b. Plant growing from ascending to vertical thickish, occasionally branched, rhizome commonly ≥ 3 mm in diameter, lacking stolons; corolla blue or violet to purple (white with blue, blue-gray, or purple eyespot in Viola communis f. priceana, white in rare albinos of various species), > 1 cm long (yellow and up to 1.4 cm in Viola rotundifolia) . . . (Key G)



Key D. Caulescent Violets with White or Yellow Flowers, and Entire or Erose Stipules

1a. Corolla white with a yellow center, ventral surface of petals pink- or violet-tinged, dorsal surface of aging flowers fading to pink or violet; stipules mostly membranous and occasionally deciduous, long-triangular, narrowly attenuate, entire . . . (2)

1b. Corolla yellow, ventral surface of petals often brown-tinged; stipules mostly or wholly herbaceous, ovate to narrowly ovate, entire or erose . . . (3)

2(1)a. Plants not densely colonial, rhizome short, lacking an elongate stoloniform extension (southern Appalachian plants occasionally produce a stoloniform rhizome); foliage nearly glabrous or upper portion of stem, petioles, and lower surface of leaf blades sparsely hirtellous, peduncles glabrous; upper leaf blades long-acuminate at apex, lower subacuminate; basal leaf blades shallowly cordate; calyx glabrous and eciliate, sepals linear-lanceolate; North America east of the Great Plains . . . Viola canadensis L.

2(1)b. Plants commonly densely colonial, rhizome continuing in an elongate stoloniform extension that often terminates in a plantlet; foliage and peduncles moderately to densely hirtellous; upper leaf blades subacuminate to acute at apex, lower acute to obtuse; basal leaf blades deeply cordate; calyx typically hirtellous and ciliate, sepals lanceolate; western Great Lakes region, northern Great Plains and Rocky Mountains . . . Viola rugulosa Greene

3(1)a. One or more cauline leaf blades deeply 3- or 5-lobed or -divided; nectar-guide lines of chasmogamous flower extending > 2/3 length of the spurred petal . . . Viola tripartita Elliott

3(1)b. Leaf blades unlobed; nectar-guide lines extending ≤ 1/2 length of spurred petal (4)

4(3)a. Larger cauline leaf blades as broad as long or broader than long . . . (5)

4(3)b. Larger cauline leaf blades distinctly longer than broad . . . (6)

5(4)a. Stems (1)2–5(6), spreading to decumbent at base during chasmogamous flowering or occasionally strongly ascending to erect in chasmogamous flower (especially in plants with few stems), becoming erect in fruit; basal leaves usually 1–3 per stem, uncommonly none; all nodes with fully developed leaves or infrequently the lowest node leafless, the 4–5 cauline leaves distributed over 1/2–4/5 of the stem; larger cauline leaf blades ovate to triangular-ovate, shallowly to moderately cordate at base, narrowly acute to abruptly acuminate at apex, the uppermost fully expanded leaf blade (typically at the second node) bearing 5–15 marginal teeth per side; foliage usually medium green, glabrous to moderately hirtellous on upper portion of stems and leaves, peduncles glabrous or uncommonly sparsely hirtellous; stipules highly variable, lanceolate to ovate, often cordate-auriculate on outer side; widely distributed over eastern North America . . . Viola eriocarpa Schwein.

5(4)b. Stems 1(2), erect; basal leaves none (very rarely 1) per stem; lowest 1–2 nodes leafless, the 2–3 cauline leaves clustered in the upper 1/5–1/3 of the stem; larger cauline leaf blades broadly ovate or broadly deltate-ovate to (deltate-)reniform, broadly cuneate to truncate at base, abruptly acute or subacuminate (in chasmogamous flower) to broadly obtuse (in fruit) at apex, the uppermost fully expanded leaf blade (typically at the second node) bearing 13–26 marginal teeth per side; foliage gray-green, stems (at least in upper portion), leaves and peduncles densely spreading-hirsute; stipules broadly ovate, rarely ovate-lanceolate, cuneate at base on both sides; restricted to Applachian Mountains and associated uplands, Northeast and Great Lakes region . . . Viola pubescens Aiton

6(4)a. Rhizome whitish; leaf blades hastate, base subcordate to deeply cordate with basal lobes parallel or divergent; upper surface of leaf blades in living material frequently bicolorous, silvery-green between the contrasting darker green veins . . . Viola hastata Michx.

6(4)b. Rhizome brown; leaf blades lanceolate, ovate- or rhombic-lanceolate, to narrowly ovate, base truncate, rounded or cuneate; leaf blade surfaces uniformly gray-green or green . . . (7)

7(6)a. Foliage green; leaf blades narrowly ovate or lance-triangular to rhombic-lanceolate, margins crenate-serrate; forests of eastern North America . . . Viola glaberrima (Ging. ex Chapm.) House

7(6)b. Foliage gray-green; leaf blades linear-lanceolate to narrowly ovate, margins subentire; grasslands and desert scrub of Great Plains and western North America . . . (8)

8(7)a. Largest leaf blades linear-lanceolate to lanceolate, ≥ 3.5 × as long as wide, base narrowly cuneate; just entering our range in Minnesota from the Great Plains Viola nuttallii Pursh

8(7)b. Largest leaf blades narrowly ovate or elliptical, < 2.6 × as long as wide, base broadly cuneate to truncate (not yet documented in our region, see “Potential Taxa”) . . . Viola vallicola A.Nelson



Key E. Caulescent Violets with Whitish to Pale Blue, Violet, Purple or Multicolored Flowers, and Fringed or Lobed Stipules

1a. Corolla strongly frontally flattened in living material; petals cream or pale blue to purple, red to orange or multicolored with yellow throat; spur short, up to 3 mm long; stipules deeply pinnately lobed with few to many lateral segments, the terminal lobe resembling the leaf blades; leaf blades linear-lanceolate to elliptical, base cuneate to truncate; plants annual or biennial, with slender rootstock . . . (2)

1b. Corolla not strongly frontally flattened in living material; petals cream, pale blue, or violet to purple with white throat; spur longer, 3–20 mm long; stipules subentire to irregularly lacerate or laciniate but not deeply lobed with leaf-like terminal lobe; leaf blades ovate to reniform, base cordate; plants perennial, with thickish rootstock . . . (5)

2(1)a. Petals shorter than the sepals or scarcely surpassing them by 1–2 mm, cream-white; sepals nearly or fully concealing capsule; native of Eurasia, sparingly cultivated but introduced widely . . . Viola arvensis Murray

2(1)b. Petals well surpassing sepals, pale blue to violet (infrequently cream-white) or multicolored; sepals neither surpassing nor concealing capsule . . . (3)

3(2)a. Leaves all cauline; petals pale blue to violet or cream-white; terminal lobe of stipules slightly larger than lateral lobes, similar in shape, with 0–3 crenations per margin; quadrate stems recurved-puberulent or -hispidulous on face directly above a leaf node but essentially glabrous on the other faces; capsules < 6 mm; seeds 1.2–1.5 × 0.6–0.8 mm; cleistogamous flowers produced; native of diverse situations, especially in alkaline floodplains . . . Viola rafinesquei Greene

3(2)b. Leaves cauline and basal; petals variously colored, distal half of upper pair of petals purple-black or borders of all petals black; terminal lobe of stipules much larger and differently shaped than lateral lobes, with (2–)4 or more crenations per margin; quadrate stems recurved-puberulent on the angles or glabrous; capsules 6–10 mm long; seeds 1.4–1.7 × 0.8–0.9 mm; cleistogamous flowers lacking; cultivated plants of abandoned homesteads, roadsides, and cemeteries . . . (4)

4(3)a. Flowers ≤ 1.5 cm long; corolla commonly with lower 3 petals cream-white or with yellow, and upper 2 violet, reddish-purple, purple or purple-black at least in distal half; native of Eurasia, widely cultivated and escaped . . . Viola tricolor L.

4(3)b. Flowers > 1.5 cm long; all petals variously colored, often with broad black border; barely persistent following cultivation (see Viola tricolor) . . . Viola × wittrockiana Gams ex Nauenb. & Buttler

5(1)a. Plants mat-forming, the current year's stems ascending at chasmogamous flowering time and persistent through winter to become prostrate and root at the nodes . . . (6)

5(1)b. Plants not mat-forming, the current year's stems ascending to erect at chasmogamous flowering time through fruiting, deciduous through winter (basal portion of stems occasionally rooting at the nodes in rare introduced Viola arcuata Blume) . . . (7)

6(5)a. Foliage glabrous except for small scattered subappressed hairs on upper surface of leaf blades (especially near the margins), peduncles and stems glabrous; upper surface of leaf blades uniformly green; stipules weakly lacerate, with marginal processes < 1/4 as long as the stipule; moist loam of riverbanks and lawns, northern and central Appalachians, Pennsylvania, Maryland, and West Virginia, disjunct in western North Carolina . . . Viola appalachiensis L.K.Henry

6(5)b. Foliage, peduncles, and stems densely puberulent; upper surface of leaf blades silvery- to gray-green with darker green veins; stipules deeply laciniate with marginal processes > 1/2 as long as the stipule; sandy loam, commonly on dolomite ledges in dry-mesic and mesic forests in the northern part of the range and under dry oak-pine forests southward, southeastern USA and sporadic northward into the central Appalachians, Western Allegheny Plateau, and Interior Lowland Plateau . . . Viola walteri House

7(5)a. Corolla pale violet with purple-black eyespot surrounding throat formed by dense and coalescing nectar-guide lines; spur 10–15 mm, as long as to longer than blade of bottom petal; all petals glabrous; stipules oblong- to linear-lanceolate, > 3 × as long as broad, weakly lacerate; margins of leaf blade remotely crenate-serrate . . . Viola rostrata Pursh

7(5)b. Corolla blue to purple, or white to cream-white, nectarguide-lines fine and inconspicuous (dense, extensive and blackish nectar-guide lines on spurred petal in Viola arcuata), lacking a dark eyespot; spur short or elongate but distinctly shorter than blade of bottom petal; lateral petals bearded; stipules lanceolate to ovate, < 3 × as long as broad, weakly to strongly lacerate or laciniate; margins of leaf blades closely crenulate, crenate or subentire . . . (8)

8(7)a. Corolla white (rarely pale violet), spurred petal with extensive dense nectar-guide lines; spur short, 1–2 mm; cauline leaf blades broader than long, ovate- to deltate-reniform; stipules subentire or minutely toothed; native of temperate eastern and tropical Asia, introduced to New Jersey and New York . . . Viola arcuata Blume

8(7)b. Corolla cream-white, blue or purple, spurred petal with few fine inconspicuous nectar-guide lines; spur moderately short to elongate, 3–7 mm; cauline leaves longer than broad to broader than long but not deltate; stipules weakly to strongly lacerate or fimbriate . . . (9)

9(8)a. Corolla cream-white; calyx ciliate; auricles prominent and quadrate; margins of leaf blades closely crenulate; stipules strongly lacerate to fimbriate . . . Viola striata Aiton

9(8)b. Corolla blue to purple; calyx eciliate (midvein of sepals occasionally puberulent in Viola adunca); auricles short and rounded; margins of leaf blade subentire, rounded-dentate or (sub)crenate; stipules minutely toothed or lacerate to strongly laciniate . . . (10)

10(9)a. Foliage, stems, and peduncles puberulent (very rarely glabrous in boreal populations); margins of leaf blades subentire to subcrenate, commonly revolute; stipules strongly laciniate . . . (11)

10(9)b. Foliage glabrous except for small scattered subappressed hairs on upper and/or lower surface of leaf blades; stems and peduncles glabrous; stipules subentire to weakly lacerate . . . Viola labradorica Schrank

11(10)a. Style abruptly expanding just below head; projections on head (when present) commonly dense, narrowly cylindrical, their length up to 1/6 the width of the style head, tip below stigmatic orifice abruptly bent upward at 90°; hairs of foliage and peduncle (when present) up to 0.3 mm long; guard cells 22–30 µm long; pollen grains 3.2–4.6 µm in diameter; transcontinental, north and east of Lake Superior in the Great Lakes and Northeast, mostly south of the US-Canadian border in the West . . . Viola adunca Sm.

11(10)b. Style uniformly cylindrical or gradually expanding to head; projections on head (when present) sparse, conical or globular, their length up to 1/10 the width of the style head, tip below stigmatic orifice gradually bent upward at 45°; hairs of foliage and peduncle (when present) up to 0.22 mm long; guard cells 25–36 µm long; pollen grains 4.1–4.9 µm in diameter; virtually restricted to central and western Canada, from northern shore of Lake Superior west to Yukon and Vancouver Island, British Columbia (not yet documented in our region, see “Potential Taxa”) . . . Viola aduncoides A.Löve & D.Löve



Key F. Acaulescent Violets with Horizontal Stoloniform Rhizomes and/or Stolons (Stolons Lacking in Viola renifolia, Commonly Lacking in Viola vittata), and White or Purple Flowers (Yellow-Flowered Viola rotundifolia is Included Here in its Summer Fruiting State, its Prostrate Stems Often Misinterpreted as a Stolon)

1a. Corolla violet (often white in Viola odorata); flower > 1 cm long; plant forming a distinct rosette and producing greenish leafless nonreproductive stolons terminating in a plantlet, or plant not forming a distinct rosette but growing from a creeping rhizome with lateral stolons, the leaves inserted individually along the length of the rhizome and stolons near the apex (flowers and fruits arising from the leaf axils); leaf blades orbiculate to reniform . . . (2)

1b. Corolla white; flower mostly ≤ 1 cm long; plant forming a distinct rosette and producing leafy summer stolons with leaves and cleistogamous fruits along their length (stolons lacking in Viola renifolia, stolons leafless and nonreproductive but terminating in a plantlet in Viola incognita, stolons commonly lacking or nonreproductive with few leaves in Viola vittata); leaves narrowly linear to reniform . . . (4)

2(1)a. Plant rosulate, growing from vertical or stoloniform rhizome with pale to greenish subherbaceous stipules, producing leafless and nonreproductive, greenish, cordlike stolons; foliage puberulent; corolla white or violet; style of chasmogamous flower with a pronounced downward-pointing hook; cleistogamous capsule purple-spotted or blotched, hirtellous; native of Eurasia, widely cultivated and also escaped to lawns, roadsides and urban woodlots . . . Viola odorata L.

2(1)b. Plant growing from a creeping pale, occasionally branching, rhizome with pink or brownish membranous stipules, producing leaves, flowers, and capsules along its length; foliage essentially glabrous; style of chasmogamous flower lacking a pronounced downward-pointing hook; cleistogamous capsule unspotted, glabrous; natives of bogs and sedge meadows in arctic and boreal North America, south to Maine, Vermont, Michigan, and Minnesota; Colorado, Arizona, and northern California . . . (3)

3(2)a. Leaves during chasmogamous flower 2–5, blades 25–50 mm long, glabrous; bracts positioned at or below middle of peduncle; lateral petals glabrous within; spur ca. 2.0 mm long, 1.5 × as long as auricles; style and stamen appendages weakly exserted and scarcely visible in living material; seeds very dark brown to black, unspotted; southward from eastern Canada in our region to Maine and New Hampshire . . . Viola palustris L.

3(2)b. Leaves during chasmogamous flower 1–2, blades 8–25 mm long during chasmogamous flower, glabrous or lower surface with fine hairs along proximal veins; bracts positioned above the middle, often near the apex of the peduncle; lateral petals sparsely bearded within; spur ca. 1.5 mm long, 2–3 × as long as auricles; style and stamen appendages prominently exserted and fully visible in living material; seeds dark gray to olive-green, blotched; southward from eastern Canada in our region to Michigan and Minnesota . . . Viola suecica Fr.

4(1)a. Leaf blades distinctly longer than broad (1.5–15 × as long as broad), ovate-lanceolate to ovate-triangular, or lanceolate to linear . . . (5)

4(1)b. Leaf blades usually as broad as long or broader than long (< 1.2 × as long as broad), ovate or orbiculate to reniform . . . (7)

5(4)a. Largest leaf blades ovate-lanceolate to ovate-triangular, 1.5–2 × as long as broad, base broadly rounded to subcordate . . . Viola primulifolia L.

5(4)b. Largest leaf blades lanceolate to linear-lanceolate in early chasmogamous flower, narrowly lanceolate to linear in fruit, 3–15 × as long as broad, base cuneate . . . (6)

6(5)a. Largest leaf blades narrowly elliptical to lanceolate, 3–6(8) × as long as broad, (5)7–29 mm broad, abruptly tapering to the petiole; gland of marginal teeth appressed to incurved, margins appearing subentire, low-serrate or shallowly (sub)crenate; summer plants producing surficial leafy stolons with 1–few cleistogamous capsules in the leaf axils; lowest sepals of chasmogamous flowers narrowly triangular to ovate-triangular, acuminate; foliage glabrous (rarely sparsely hirtellous in extreme southern populations); seeds obovoid, 1.1–1.4 × 0.8–1.0 mm, dark olive-brown; widespread in northeastern and central North America but absent from the extreme southeast Atlantic Coastal and Gulf Coastal Plains . . . Viola lanceolata L.

6(5)b. Largest leaf blades linear to linear-lanceolate, 8–15 × as long as broad, (2)4–9(13) mm broad, tapering gradually to the petiole; gland of marginal teeth ascending to spreading, margins commonly appearing denticulate; summer plants rarely producing surficial stolons, if present these leafless and nonreproductive (occasionally terminating in a plantlet); lowest sepals of chasmogamous flowers linear-lanceolate to lance-triangular, acuminate to attenuate; foliage glabrous to moderately hirtellous; seeds 1.0–1.2 × 0.7–0.9 mm, broadly obovoid, dull gray-brown; central and southern Atlantic and Gulf Coastal Plains . . . Viola vittata Greene

7(4)a. Plant growing from a vertical twisted rhizome, lacking stolons; leaf blades broadly ovate or suborbiculate to reniform, widely spreading or more often prostrate on the substrate in living material, especially during fruit, either glabrous or wholly densely hirsute or one or both leaf blade surfaces densely hirsute; lateral petals beardless (rarely sparsely bearded) within; cleistogamous capsule purple-spotted, on short prostrate peduncle; seeds orange-brown to brown . . . Viola renifolia A.Gray

7(4)b. Plant growing from a horizontal stoloniform rhizome, producing surficial or subsurficial stolons especially during summer fruit (rhizome vertical and “stolon” a horizontal surficial stem in Viola rotundifolia); leaf blades elevated and spreading in living material, glabrous to variously pubescent (prostrate on the substrate in living material, especially during fruit, in Viola rotundifolia); lateral petals beardless or bearded; cleistogamous capsule unspotted on erect peduncle, or purple-spotted to blotched on prostrate peduncle; seeds tan or medium to dark brown or blackish-brown . . . (8)

8(7)a. Rhizome vertical, ≥ 3 mm in diameter; leaf blades thickish in living material, broadly elliptical to orbiculate; stipules entire along margins; stolon-like summer stem(s) bearing 0–1 leaf and terminating in a reduced cyme of 1–3 purple-spotted or blotched cleistogamous capsules; seeds ivory to light orange-brown . . . Viola rotundifolia Michx., in part

8(7)b. Rhizome horizontal and stoloniform, < 3 mm in diameter; leaf blades thin in living material, variously shaped; stipules glandular-fringed along margins; stolons leafless or bearing leaves and/or cleistogamous capsules at nodes along their length, occasionally terminating in a plantlet; cleistogamous capsules unspotted or spotted to blotched; seeds light brown to olive-brown or blackish . . . (9)

9(8)a. Leaf blades uniformly green on both surfaces (lower surface occasionally drying orange-tinged), glabrous (petioles may be glabrous or pubescent), orbiculate, mostly broadly rounded at apex, margins subentire to shallowly crenate; cleistogamous capsules green, unspotted, on erect peduncles; seeds 0.8–1.4 × 0.7–0.8 mm, medium to dark olive-brown or brownish-black, with minute black spots . . . Viola minuscula Greene

9(8)b. At least some leaf blades broader than long, bicolorous with darker green upper surface and paler lower surface, usually pubescent on one or both surfaces, obtuse to acute (acuminate) at apex, blade margins most often shallowly serrate; cleistogamous capsules with dense fine purple spots, on prostrate to arching peduncles; seeds 1.2–2.2 × 0.7–1.3 mm, brown or brownish-blackish, unspotted . . . (10)

10(9)a. Leaves glabrous except for scattered appressed hairs on upper surface of leaf blades, peduncles glabrous; largest leaf blades with proportionally short basal lobes < 1/4 of total length of blade, sinus narrow with inner edges of basal lobes attingent or overlapping in living material, acute at apex, margins shallowly crenate; petioles and peduncles commonly red-tinged or -spotted; all petals glabrous; cleistogamous capsules 6.5–8 mm long; seeds 1.2–1.3 × 0.7–0.8 mm, brownish-black; primarily Appalachian Mountains and adjacent uplands, common at higher elevations . . . Viola blanda Willd.

10(9)b. Petioles and/or one or both surfaces of leaf blades glabrous or sparsely to densely hirsute, peduncles glabrous to hirsute; largest leaf blades with proportionally longer basal lobes > (1/4–)1/3 of total length of blade, sinus broad with basal lobes well separated or divergent in living material, typically obtuse to rounded at apex, margins low-serrate with noticeable teeth (check at widest point of leaf); petioles and peduncles not red-tinged or -spotted; lateral petals bearded; cleistogamous capsules 7–14 mm long; seeds 1.6–2.2 × 1.0–1.3 mm, light to medium brown; widely distributed in Appalachians, Northeast and Great Lakes regions, in central and southern Appalachians most common at lower elevations . . . Viola incognita Brainerd



Key G. Acaulescent Violets Lacking Stolons, with Blue or Violet to Purple Flowers (Yellow in Viola rotundifolia, White or Weakly Violet-Tinged in Viola patrinii, White with Broad Blue, Blue-Gray, or Purple Eyespot in Viola communis f. priceana)

1a. Corolla yellow; leaf blades broadly elliptical to orbiculate, nearly or completely prostrate on substrate, especially during fruit . . . Viola rotundifolia Michx., in part

1b. Corolla blue or violet to purple (white with broad blue, blue-gray, or purple eyespot in Viola communis f. priceana, rarely white in sporadic albinos of various species); leaf blades various (commonly prostrate on substrate during fruit in Viola hirsutula Brainerd, at least the outer leaves prostrate in Viola fimbriatula) . . . (2)

2(1)a. At least the largest leaf blades notched, incised, coarsely toothed, lobed or dissected, or bearing linear marginal processes . . . (3)

2(1)b. All leaf blades undivided, margins merely crenate or serrate (pectinately serrate in Viola pectinata E.P.Bicknell; occasional Viola edulis in early chasmogamous flower without lobed leaf blades may key to Viola langloisii Greene just south of our range but has ovate-triangular sepals acuminate from the middle and shorter broader auricles < 2 mm long) . . . (27)

3(2)a. All petals glabrous within; corolla concolorous blue or lower 3 petals blue and upper pair purple-black; stipules long-adnate to petiole; rhizome erect, barrel-like; cleistogamous flowers absent; dry sandy, gravelly, or rocky soils in oak or oak-pine forests, barrens and sand prairies, and slopes . . . (4)

3(2)b. Lateral petals bearded within, occasionally the spurred petal also; corolla concolorous except for expanded white area from the throat in a few species; stipules free; rhizome horizontal or ascending, occasionally branching, not barrel-like; cleistogamous flowers produced; diverse substrates and habitats . . . (5)

4(3)a. Largest leaf blades deeply “triternately” dissected, with secondary divisions on each primary lobe deeply divided into multiple crowded narrowly linear ultimate segments; endemic to Shale Barrens region, southwestern New Jersey and Pennsylvania to Virginia and eastern West Virginia . . . Viola pedata L. subsp. cuneatiloba (Brainerd ex Fernald) H.E.Ballard

4(3)b. Largest leaf blades deeply pedately divided, with primary lobes undivided or with a short subapical tooth on one or both sides (blades rarely obrhombic or obovate with 1–2 shallow apical crenations or short broadly rounded lobes due to partial fusion of leaf segments); widespread in eastern North America . . . Viola pedata L. subsp. pedata

5(3)a. Plant homophyllous, all blades lobed or dissected (plants with largest leaf blades shallowly lobed are frequent where Viola sororia and other species with unlobed leaf blades are locally sympatric with species producing deeply divided leaves and are de novo hybrids; they will not key readily and must be inferred by association with the parent species) . . . (6)

5(3)b. Plant heterophyllous, producing leaf blades with lobes, coarse teeth, or incisions during chasmogamous flowering and cleistogamous fruiting, and undivided leaf blades in very early spring and late autumn (often retaining one or more undivided blades) . . . (11)

6(5)a. Petioles glabrous, leaf blades sparsely appressed-hirtellous on veins, margins appressed-ciliolate; spurred petal densely bearded; lowest sepals lanceolate, sharply acute; auricles prominent, elongating in fruit to 6 mm; cleistogamous capsules green drying tan, unspotted, on erect peduncles nearly or fully as long as petioles; seeds 1.3–2.0 × 0.9–1.3 mm, narrowly obovoid, medium brown to orange-brown, unspotted . . . (7)

6(5)b. Foliage glabrous, or petioles and at least lower surface of leaf blades hirsute, margins often ciliate; spurred petal glabrous; lowest sepals oblong to ovate, obtuse to rounded at apex (lance- to ovate-triangular and acuminate in Viola monacanora); auricles short and rounded, not elongating in fruit; cleistogamous capsules purple-spotted, on prostrate or arching peduncles shorter than petioles; seeds 1.6–2.4 × 1.1–1.7 mm, various but not medium brown to orange-brown, mostly spotted or blotched . . . (8)

7(6)a. Largest leaf blades narrowly to broadly ovate in outline, base subtruncate to cordate, biternately divided into 7 or 9 ultimate lanceolate segments, terminal ultimate segment of terminal primary division commonly distinctly broader and well surpassing lateral segments; sepals eciliate (auricles infrequently irregularly ciliolate); seeds 1.3–1.9 × 0.9–1.3 mm; moist to wet sandy or peaty soils of brackish marshes, banks of streams and rivers, ditches along fields and in meadows, and forest clearings, Atlantic Coastal Plain . . . Viola brittoniana Pollard

7(6)b. Largest leaf blades reniform in outline, base broadly rounded to subcordate, triternately divided into (13)17–25 narrowly linear ultimate segments, terminal ultimate segment of terminal primary division neither distinctly broader nor longer than lateral segments; calyx usually ciliate; seeds 1.7–2.0 × 1.1–1.3 mm; rich mesic loam of blacksoil prairies and savanna openings in the Midwest to the Great Plains and southwestern North America, slightly disjunct in southern Ontario and northern Ohio . . . Viola pedatifida G.Don

8(6)a. Foliage glabrous (petioles uncommonly sparsely hirsute in Viola monacanora); calyx eciliate; lowest sepals acuminate; montane North Carolina and Virginia . . . (9)

8(6)b. Foliage moderately to densely hirsute; calyx ciliate; lowest sepals ovate-lanceolate to broadly ovate, obtuse to broadly rounded (occasionally acute in Viola baxteri House) . . . (10)

9(8)a. Largest leaf blades during chasmogamous flower narrowly ovate-triangular and palmatifid to subbiternate, blades in fruit ovate, biternately divided into 9–11(13) usually slightly falcate ultimate lobes, these becoming asymmetrically angulate at apex in fruit, outer margins of lobes with 1–3 incurved teeth, primary divisions not narrowed or constricted at base; lower surface of leaf blade not distinctly paler than upper, purple-tinged; lowest sepals lance- to ovate-triangular, acute or acuminate; seeds 1.8–2.1 × 1.2–1.4, blackish with minute raised black reticulations; moist loam soils in rich mesic rocky woodlands in the Blue Ridge Mountains of western Virginia and northwestern North Carolina . . . Viola monacanora J.L.Hastings & H.E.Ballard

9(8)b. Largest leaf blades during chasmogamous flower ovate and deeply bi- to subtriternately divided, blades in fruit orbiculate to reniform and tri- to tetraternately dissected into 17–27 narrowly linear ultimate lobes, these narrowly rounded at apex, margins entire or with a minute subapical tooth on either margin, primary divisions distinctly constricted at base into a very slender elongate “petiolule”; lower surface of blade distinctly paler than upper, not purple-tinged; lowest sepals ovate-lanceolate to narrowly ovate, broadly acute to obtuse; seeds 1.7–2.4 × 1.1–1.5 mm, gray, gray-brown, or light to medium (reddish-)brown, unspotted or with sparse to dense minute raised black spots; dry sandy shale-derived soils of woodland borders surrounding shale barrens in Allegany and Bath counties, Virginia . . . Viola tenuisecta Zumwalde & H.E.Ballard

10(8)a. Largest leaf blades biternately to subtriternately divided into 9–13(15) narrowly linear-lanceolate lobes < 3 mm wide (in chasmogamous flower), the lateral second-order lobes of the terminal primary division attached medially, second-order lobes usually with a prominent slender spreading sharply acute tooth or short lobe on each side; primary divisions commonly narrowed at base to slender “petiolules”; foliage and peduncles not purple-tinged; lowest sepals acute or obtuse; seeds ivory, unspotted, or occasionally with small weak light brown blotches or streaks; limestone prairies and prairie-like openings; lower elevations in eastern Great Lakes region, western New York to southwestern Ontario and southeastern Michigan, south to southwestern Pennsylvania, southwestern Ohio, and northeastern Indiana . . . Viola baxteri House

10(8)b. Largest leaf blades (sub)biternately divided into 7 or 9 broadly linear or lanceolate lobes > 3 mm wide (in chasmogamous flower), the second-order lobes of the terminal primary division attached medially or basally, second-order lobes entire or with 1–2 inconspicuous short appressed or incurved teeth on each side; primary divisions not distinctly narrowed at base; lower surface of leaf blades, petioles, and peduncles often purple-tinged; lowest sepals obtuse to rounded; seeds light brown with small prominent dark orange-brown streaks, or light to medium gray with small prominent darker gray blotches or streaks; dry-mesic woodlands, not consistently associated with limestone; widely distributed in Appalachian Mountains (almost exclusively Ridge and Valley province in central Appalachians), northeastern and southeastern Piedmont, Interior Lowland Plateau southward, Massachusetts and Vermont to New York, south to northern Georgia and western Tennessee . . . Viola subsinuata (Greene) Greene

11(5)a. At least some petioles prominently winged; lowest sepals linear-lanceolate to lance-triangular, acuminate; spurred petal bearded within; cleistogamous capsule unspotted, on erect peduncle (declined in Viola fimbriatula); auricles prominent, elongating in fruit to 3 mm or more; in dry acidic sandy or gravelly soils in oak or oak-pine forests, barrens, and forest borders, in the Atlantic Coastal Plain and Piedmont, Appalachian Mountains and southern Great Lakes regions . . . (12)

11(5)b. Petioles not winged; lowest sepals lanceolate to (more commonly) ovate-lanceolate, oblong or ovate, acuminate to rounded; spurred petal glabrous or bearded within; cleistogamous capsule unspotted or purple-spotted or -blotched, on erect or declined to prostrate peduncle; auricles short and rounded or prominent, remaining short or weakly to strongly elongating in fruit; in diverse substrates and habitats, in various places in our region . . . (15)

12(11)a. Foliage densely hirtellous, uniform green; at least the outer leaves widely spreading or prostrate on the substrate in living material; petioles shorter than (in chasmogamous flower) to 2 × longer (in fruit) than blades; largest leaf blades broadly elliptical to narrowly oblong-ovate or narrowly ovate-triangular in outline, in fruit developing 1–2(3) coarse apically oriented teeth at base on each side; peduncle hirtellous; calyx ciliate; corolla purple, petals broadly rounded, spurred petal not medially compressed; peduncle of cleistogamous capsule declined; seeds 1.4–1.9 × 0.9–1.3 mm, medium to dark brown or gray-brown, unspotted or with small weak darker blotches . . . Viola fimbriatula Sm., in part

12(11)b. Foliage glabrous or surfaces of leaf blades sparsely appressed-hirsute, blue-green, lower surface of blades, petioles, and peduncles tinged with purple; leaves erect in living material; petioles > 2 × as long as leaf blades; largest leaf blades either with terminal division long and narrowly linear to oblong-linear and 2–4 elongate linear lobes or processes at the base or distributed along the margin on each side, or ovate- or lance-triangular with 1–3 short broadly triangular basal lobes on each side; peduncle glabrous; calyx eciliate; corolla violet, petals commonly emarginate, spurred petal commonly medially compressed; peduncle of cleistogamous capsule erect; seeds 1.4–2.2 × 0.9–1.5 mm, pinkish-gray to dark gray with prominent darker streaks and spots . . . (13)

13(12)a. Largest leaf blades with terminal primary division ovate- to lance-triangular, with 1–3 short broadly triangular basal lobes on each side; Atlantic Coastal Plain in the northern portion of its range, the upper Atlantic Coastal Plain and Piedmont in Virginia and the Carolinas, Massachusetts south to Georgia . . . Viola emarginata sensu stricto,) in part

13(12)b. Largest leaf blades either with terminal division long and narrowly linear to oblong-linear and 2–4 elongate linear lobes or processes at the base or distributed along the margin on each side; Piedmont and Appalachian Mountains in southern Virginia to western South Carolina . . . (14)

14(13)a. Largest leaf blades resembling a walkingstick insect (e.g., Diapheromera femorata (Say)), each side with 2–4 long slender variously bent processes distributed along its length; south-central Virginia and central North Carolina . . . Viola emarginata (phasmatifolia variant)

14(13)b. Largest leaf blades resembling a sword, each side with 1–2 long slender spreading falcate-linear processes at the base, occasionally with an additional process on one side a little above the base; bimodal and sporadic in the Appalachian Mountains, southwestern Virginia, and southwestern North Carolina and adjacent northwestern South Carolina . . . Viola emarginata (xiphophylla variant)

15(11)a. Largest leaf blades distinctly longer than broad (blade length:width ratio ≥ 1.3) . . . (16)

15(11)b. Largest leaf blades slightly longer than broad to broader than long (blade length:width ratio < 1.3) . . . (18)

16(15)a. Leaves erect in living material; leaf blades narrowly elliptical or ovate-lanceolate with small basal teeth or lobes during chasmogamous flower, sagittate or lance-triangular with larger slender basal teeth or linear-falcate lobes during fruit, teeth or lobes ≤ 1/4 length of the midrib; foliage glabrous or (more commonly) sparsely to moderately hirtellous; lowest sepals linear-lanceolate to lance-triangular; spurred petal densely bearded within; inhabiting upland or wetland sites in dry to seasonally moist acidic sandy soils in sand prairies and oak barrens, interdunal swales, and lakeshores; widespread throughout much of eastern North America, mostly absent from Atlantic and Gulf Coastal Plains . . . Viola sagittata Aiton, in part

16(15)b. Leaves erect or widely spreading in living material; leaf blades narrowly ovate-triangular to narrowly ovate or broadly oblong-lanceolate, lateral lobes short and angulate during chasmogamous flower but elongating to ≥ 1/4 length of the midrib in fruit (in Viola edulis), or variously short and elliptical or longer and linear and ≥ 1/4 length of the midrib (in Viola viarum Pollard); foliage glabrous; lowest sepals linear-lanceolate to ovate-triangular; spurred petal glabrous or sparsely bearded within; inhabiting diverse substrates of bottomland sites along streams and rivers of the Atlantic Coast or central and lower Midwest . . . (17)

17(16)a. Leaves widely spreading in living material; leaf blades narrowly ovate-triangular, lateral lobes short and angulate during chasmogamous flower and elongating during fruit; lowest sepals ovate-triangular; spurred petal glabrous within; inhabiting floodplains of streams and rivers along the Atlantic and Gulf Coastal Plains . . . Viola edulis Spach, in part

17(16)b. Leaves ascending to erect in living material; leaf blades ovate-triangular to narrowly ovate, slender lateral lobes already 1/4–1/2 midrib length during chasmogamous flower; lowest sepals linear-lanceolate to lanceolate; spurred petal sparsely bearded within; inhabiting thin alluvial soils amid limestone gravel or rubble or cracks in limestone bedrock along streams and rivers, mainly in the northern Ozarks and Missouri River drainage of the central and lower Midwest, east to northern Illinois and north to southeastern South Dakota . . . Viola viarum Pollard, in part

18(15)a. Foliage glabrate to hirsute (occasionally essentially glabrous in Viola stoneana House); peduncles glabrous or sparsely to moderately hirsute; calyx eciliate or ciliate; lowest sepals linear-lanceolate to ovate, acuminate to rounded; auricles short and rounded and not elongating in fruit (prominent and weakly elongating in fruit in Viola stoneana); cleistogamous capsule finely to heavily purple-spotted or -blotched, on initially prostrate peduncle arching upward just before dehiscence, peduncle much shorter than petioles (peduncle ascending to erect and as long as to longer than shorter petioles in Viola stoneana) . . . (19)

18(15)b. Foliage glabrous; peduncles glabrous; calyx eciliate, lowest sepals acute or acuminate (calyx occasionally ciliate, sepals obtuse to rounded in Viola egglestonii sensu stricto); auricles short and not elongating in fruit, or prominent and elongating in fruit; cleistogamous capsule unspotted or finely to heavily spotted or blotched with red, reddish-purple, or purple, on erect or suberect peduncle, peduncle as long as to longer than shorter petioles (prostrate or arching upward or ascending, much shorter than petioles in Viola egglestonii sensu stricto and Viola egglestonii [Canada variant]) . . . (23)

19(18)a. Largest lobed leaf blades biternately divided, the terminal primary division bearing lateral lobes (veins of these lateral lobes will connect with the midrib or with veins of the terminal primary division) . . . (20)

19(18)b. Largest lobed leaf blades pedately divided, the terminal primary division lacking lateral lobes (any shorter intermediary lobes between the terminal and lateral primary divisions will have veins connecting to the veins of the lateral primary divisions) . . . (21)

20(19)a. Central and lateral lobes of terminal primary division linear-lanceolate to lanceolate, lateral lobes inserted at or just above the base of the central lobe, strongly ascending; base of primary divisions not or only weakly constricted to a long slender “petiolule”; petioles and lower surface of leaf blades sparsely to densely hirtellous or hirsute, margins of blades ciliate; chasmogamous and cleistogamous peduncles glabrous or hirsute; calyx ciliate; lowest sepals relatively short, lanceolate or lance-triangular to ovate, acuminate to obtuse or rounded; seeds pale golden-yellow or tan to light red-brown with small weak or prominent streaks and blotches; Ridge and Valley province of the Appalachian Mountains, southern Pennsylvania south to North Carolina and eastern Tennessee . . . Viola palmata (pseudostoneana variant)

20(19)b. Central and lateral lobes of terminal primary division rhombic-lanceolate, lateral lobes inserted well above the base of the central lobe, widely divergent; base of terminal and lateral primary divisions usually constricted to a long slender “petiolule”; foliage essentially glabrous, or petioles and lower surface of leaf blades sparsely hirsute and margins of blades sparsely ciliolate; chasmogamous and cleistogamous peduncles glabrous; calyx eciliate; lowest sepals lance-triangular, acuminate; seeds ivory to tan or light gray-brown, unspotted or with weak brown rectangular blotches; rich mesic forests along “fall line” between lower Piedmont and upper Atlantic Coastal Plain, New Jersey south to central Virginia, disjunct in east-central North Carolina . . . Viola stoneana House

21(19)a. Larger leaf blades shallowly to moderately divided into 3 or 5 lobes, central lobe of terminal primary division narrowly ovate or ovate-triangular, significantly larger than lateral primary lobes or intermediary lobes between terminal and lateral primary divisions, primary divisions separated by sinuses not usually > 2/3 the distance to petiole summit (shallowly lobed plants in the range of Viola palmata var. dilatata are probable de novo hybrids with Viola sororia and other species with unlobed leaf blades); peduncles essentially glabrous or sparsely hirsute; northeastern USA and southern Ontario southward into the southern Appalachian Mountains and associated uplands, mostly absent from Lower Piedmont and southeastrn Atlantic Coastal Plain, the southern limit in the Gulf States and Lower Midwest unclear . . . Viola palmata L. var. triloba (Schwein.) Ging.

21(19)b. Larger leaf blades deeply divided into (3)5 or 7 lobes, lobes approximately equal in size and length, primary divisions separated by sinuses nearly or fully to petiole summit; peduncles moderately hirsute; western Virginia, or Piedmont, Atlantic and Gulf Coastal Plains, and Lower Midwest . . . (22)

22(21)a. Uppermost lobes of lateral primary divisions (or longest axis of lateral primary divisions if not deeply cleft or divided) spreading to ascending, lateral primary divisions occasionally scarcely to weakly cleft and appearing falcate, lunate or “dilated”, the smallest lowest lobes at the base of the lateral primary division (if any) not usually overlapping in living material; foliage, peduncles and calyces gray-green to medium green, commonly lacking red-purple or purple pigmentation; chasmogamous and cleistogamous peduncles and calyces green; widespread at lower elevations of Piedmont and Atlantic and Gulf Coastal Plains in southeastern USA, and Lower Midwest . . . Viola palmata L. var. palmata

22(21)b. Uppermost lobes of lateral primary divisions widely divergent, lateral primary divisions always deeply bilobate into 2 major lobes, the lowest major lobe with a third small lobe near the base, these smallest lobes overlapping in living material; foliage color gray- or blue-green, lower surface of leaf blades strongly tinged with purple, peduncles and calyces strongly spotted with red-purple or purple; sporadic and rare in Ridge and Valley province of the Appalachian Mountains in western Virginia . . . Viola palmata (avipes variant)

23(18)a. Largest leaf blades deeply biternately divided nearly to petiole summit into (5)7 or 9 lobes (biternately divided leaf blades occasionally produced by Viola septemloba Leconte, which is keyed out in 24a), the terminal primary division narrowly lanceolate and not much broader than its lateral lobes or the lobes on the lateral primary divisions; lowest sepals oblong-lanceolate to ovate, obtuse to broadly rounded; auricles short and rounded, not elongating in fruit; spurred petal sparsely to densely bearded within; cleistogamous capsule unspotted, on prostrate to arching peduncle much shorter than petioles; seeds 2.2–2.7 × 1.5–1.7 mm, medium to dark brown, unspotted; upland limestone cedar glades of Interior Highlands region, southern Indiana south to northwestern Georgia and northern Alabama . . . Viola egglestonii Brainerd sensu stricto

23(18)b. Largest leaf blades shallowly to deeply pedately divided into 3, 5, or 7(9) lobes (rarely biternately divided in Viola septemloba), the terminal primary division broadly lanceolate or ovate-lanceolate, oblong or ovate to rhombic-ovate, distinctly to much broader than any intermediary lobes between the terminal and lateral divisions as well as the lobes of the lateral primary divisions (rarely all lobes somewhat narrowly linear in Viola septemloba); lowest sepals linear-lanceolate to ovate-triangular, acuminate from near base or middle to a sharply acute apex (rarely obtuse in Viola egglestonii [Canada variant]); auricles prominent, weakly to strongly elongating to 3 mm in fruit; spurred petal glabrous within (sparsely bearded in Viola viarum, densely bearded in Viola septemloba); cleistogamous capsules unspotted, on ascending to erect peduncles as long as to longer than the petioles (much shorter than the petioles in Viola egglestonii [Canada variant]); seeds dark bronze and unspotted, or brown with minute black spots or reticulations (seeds unknown in Viola egglestonii [Canada variant]); inhabiting pine savannas (Viola septemloba), bottomland sites along streams and rivers in the Atlantic and Gulf Coastal Plains and lower Midwest Missouri River drainage (Viola edulis and Viola viarum), or plantings and lawns in suburban areas in and near Ottawa, ON, and Montreal, QC (Viola egglestonii [Canada variant]) . . . (24)

24(23)a. Largest leaf blades moderately to deeply pedately divided into (3)5 or 7(9) lobes (rarely biternaly divided), terminal primary division narrowly oblong-linear to broadly elliptical or rhombic-ovate, lateral lobes commonly much narrower and linear-lanceolate to lanceolate, lobes divergent on blades with 5 or more lobes, lowest lobe downward-pointing; blade margins entire or subentire; spurred petal densely bearded; cleistogamous capsule unspotted, on tall erect peduncle surpassing some petioles; seeds (1.5)1.9–2.5 × 1.4–1.6 mm, brownish-black, unspotted; dry to seasonally moist sand of frequently burned long-leaf pine savannas . . . Viola septemloba Leconte

24(23)b. Largest leaf blades shallowly to deeply pedately divided with 3, 5, or 7 lobes, terminal primary division linear-oblong, lanceolate or narrowly lance-triangular to narrowly oblong-ovate, smaller lobes linear-lanceolate, oblong or falcate-angulate and ascending to spreading, lateral primary divisions lacking a distinct downward-pointing lobe; blade margins prominently incurved-serrate or crenate-serrate; spurred petal glabrous (Viola edulis, Viola egglestonii [Canada variant]) or sparsely bearded within (Viola viarum); cleistogamous capsule unspotted (Viola edulis, Viola egglestonii [Canada variant]) or finely to heavily spotted or blotched with red or purple (Viola edulis), on ascending to erect peduncle surpassing some petioles (Viola edulis) or on prostrate peduncle much shorter than petioles (Viola egglestonii [Canada variant], Viola viarum); seeds various; bottomland sites in diverse substrates along rivers and streams or swamps (Viola edulis, Viola viarum) or or plantings and lawns in suburban areas (Viola egglestonii [Canada variant]) . . . (25)

25(24)a. Leaves widely spreading to ascending in living material; leaf blades shallowly 3- to 5-lobed, lobes of lateral primary divisions comparatively short and broad, trapezoidal to ovate-lanceolate; lowest sepals oblong to ovate-triangular, acuminate from the middle; spurred petal glabrous within; cleistogamous capsule unspotted, on ascending to erect peduncle equaling or surpassing petioles; inhabiting sandy or silty soils of floodplains, swamps and hammocks on the Atlantic Plain . . . Viola edulis Spach, in part

25(24)b. Leaves ascending to erect in living material; leaf blades deeply 5-lobed, lobes of lateral primary divisions comparatively long and slender, linear-oblong or narrowly lanceolate; lowest sepals linear-lanceolate to lanceolate, acuminate from near the base; spurred petal glabrous (Viola egglestonii [Canada variant]) or sparsely bearded (Viola viarum) within; cleistogamous capsule unspotted, on ascending peduncle much shorter than petioles (Viola egglestonii [Canada variant]) or finely spotted with red or purple, on ascending to erect peduncle equaling or surpassing shorter petioles (Viola viarum) . . . (26)

26(25)a. Spurred petal glabrous within; lateral petal beards very short, not obscuring the throat; cleistogamous capsule unspotted, on ascending peduncle much shorter than petioles; plantings and lawns in and around Ottawa, ON, and Montreal, QC, also adventive in Europe and Korea . . . Viola egglestonii (Canada variant)

26(25)b Spurred petal sparsely bearded within; lateral petal beards moderately long, obscuring the throat; cleistogamous capsule finely spotted with red or purple, on ascending to erect peduncle equaling or surpassing shorter petioles; inhabiting thin alluvial soils amid limestone gravel or rubble or cracks in limestone bedrock along streams and rivers, mainly in the northern Ozarks and Missouri River drainage of the central and lower Midwest, east to northern Illinois and north to southeastern South Dakota . . . Viola viarum Pollard, in part

27(2)a. At least some petioles narrowly or broadly winged along much or all of their length; largest leaf blades distinctly longer than broad; lowest sepals linear-lanceolate, acuminate; auricles prominent, elongating in fruit, erose (auricles short and entire, remaining < 1 mm in fruit in Viola patrinii); cleistogamous capsule unspotted, on declined or erect peduncle; in dry acidic sandy or gravelly soils of oak or oak-pine forests, barrens, and forest borders (sidewalk cracks or mulch of gardens in Viola patrinii) . . . (28)

27(2)b. Petioles not noticeably winged; largest leaf blades longer than broad to broader than long; lowest sepals lanceolate to (more commonly) ovate-lanceolate, oblong or ovate, acuminate to rounded; auricles inconspicuous and remaining short and rounded, or prominent and elongating in fruit and often erose; cleistogamous capsule unspotted or spotted, on prostrate, declined or erect peduncle; in diverse substrates and habitats . . . (32)

28(27)a. Petioles and lower surface of leaf blades moderately to densely hirtellous (rarely glabrous); at least the outer leaves widely spreading or prostrate on the substrate in living material; petioles shorter than leaf blades (chasmogamous flower) to 2 × as long as blades (cleistogamous fruit); largest leaf blades elliptical or narrowly oblong-ovate in outline; peduncle hirtellous; calyx ciliate; corolla purple, petals broadly rounded, spurred petal not medially compressed; peduncle of cleistogamous capsule declined; seeds medium to dark brown or gray-brown, unspotted or with small weak darker blotches . . . Viola fimbriatula Sm., in part

28(27)b. Foliage glabrous or surfaces of leaf blades sparsely appressed-hirsute near margins and margins ciliate; leaves ascending to erect in living material; petioles > 2 × as long as leaf blades (shorter in long-leaved Viola patrinii); largest leaf blades narrowly oblong- or ovate-triangular, triangular or deltate-triangular; peduncle glabrous; calyx eciliate; corolla white or weakly violet-tinged to violet; petals occasionally emarginate and spurred petal commonly medially compressed; peduncle of cleistogamous capsule erect; seeds pinkish-gray to dark gray with streaks and spots (Viola emarginata) or yellow-brown to dark brown (Viola patrinii) . . . (29)

29(28)a. Stipules 2/3-adnate to petiole; petioles broadly winged, especially in distal half; corolla white or weakly tinged with violet; spurred petal glabrous within; spur slender and cylindrical, > 2–3 × as long as tall; lateral petal beards short, exposing throat in living material; auricles of cleistogamous capsule short and narrowly rounded or ovate-triangular, ≤ 1 mm long; seeds yellow-brown to dark brown; native of Asia, introduced through plantings to Connecticut and New York . . . Viola patrinii Ging.

29(28)b. Stipules free; petioles narrowly winged; spurred petal glabrous or bearded within; corolla violet; spur stout, ≤ 1.5 × as long as tall; lateral petal beards long, mostly obscuring throat in living material; auricles of cleistogamous capsule elongate to 3 mm or longer; seeds pinkish-gray to dark gray with streaks and spots; native to dry oak and oak-pine woodlands or wet prairies . . . (30)

30(29)a. Petals commonly emarginate; spurred petal commonly medially compressed; at least some petioles broadly winged; dry sandy soils of open dry oak and oak-pine woodlands and forest edges on the Piedmont and Atlantic Coastal Plain . . . Viola emarginata sensu stricto, in part

30(29)b. Petals broadly rounded; spurred petal not medially compressed; at least some petioles narrowly winged; various habitats in the Lower Midwest . . . (31)

31(30)a. Outline of largest leaf blades concavely tapering to narrowly acuminate or narrowly rounded apex; open dry oak and oak-pine woodlands and forest edges, Central and Lower Midwest, West Virginia and southern Ohio, south to northern Alabama, Louisiana, and northern Arkansas . . . Viola emarginata (Kentucky variant)

31(30)b. Outline of largest leaf blades convexly tapering to (broadly) rounded apex; low wet prairies, southern Missouri and eastern Kansas south to southeastern Oklahoma (not yet documented in our region, see “Potential Taxa”) . . . Viola emarginata (Lower Midwest variant)

32(27)a. All petals glabrous within (lateral petals densely bearded within in Viola inconspicua); spur ≥ 2 × as long as thick, cylindrical or club-shaped; stipules at least half-adnate to petioles . . . (33)

32(27)b. Lateral petals bearded within, spurred petal in some species bearded; spur < 1.5 × as long as thick, rounded; stipules free . . . (35)

33(32)a. Leaf blades narrowly ovate to ovate, base deeply cordate with inner edges of basal lobes commonly overlapping in living material; petiole and lower surface of leaf blades glabrous, upper surface of blades with scattered subappressed hairs; circumboreal, Greenland and Newfoundland and Labrador to Alaska, south to Rhode Island, Pennsylvania, Wisconsin, northern Minnesota, and northwest Rocky Mountains; disjunct in South Dakota and Colorado; Eurasia . . . Viola selkirkii Pursh ex Goldie

33(32)b. Leaf blades linear-oblong or narrowly ovate-triangular to narrowly deltate-triangular, base cuneate to cordate with non-overlapping or divergent lobes; leaves glabrous or puberulent; native to Asia, introduced in North America . . . (34)

34(33)a. Spur 1–3 mm long; lateral petals densely bearded within; leaves glabrous (blades and/or petioles rarely puberulent); largest leaf blades narrowly deltate-triangular, base broadly cordate with divergent basal lobes, margins concavely tapering from widest point on leaf blade to the apex; native of Asia, introduced to southeastern USA and Maine . . . Viola inconspicua Blume

34(33)b. Spur 3–8 mm long; lateral petals glabrous (rarely sparsely bearded) within; leaf blades sparsely puberulent (rarely glabrous); largest leaf blades narrowly ovate, base subcordate to shallowly cordate with downward-pointing basal lobes, margins mostly convexly tapering from widest point on leaf blade to the apex; native of Asia, introduced to northeastern U.S. . . . Viola japonica Langsd. ex Ging.

35(32)a. Leaves spreading to prostrate on the substrate in living material; upper surface of leaf blades silvery- or gray-green with contrasting dark green or red-purple veins, lower surface purple-tinged; foliage glabrous except for conspicuous stiff ascending or spreading hairs uniformly distributed over upper surface of leaf blade; calyx eciliate; lowest sepals oblong to ovate, obtuse to rounded; spurred pet densely bearded; cleistogamous capsule purple-spotted, on initially prostrate peduncle shorter than petioles; seeds 1.5–2.1 × 1.1–1.4 mm, light brown, commonly with slightly darker streaks and spots . . . Viola hirsutula Brainerd

35(32)b. Leaves strongly ascending to erect in living material (at least outer leaves widely spreading to prostrate in Viola fimbriatula); upper surface of leaf blades uniformly green, lower surface green or purple tinged; foliage glabrous or variously pubescent, if hairs confined to upper surface of leaf blade, then these are very small, scattered, and subappressed; calyx and lowest sepals, cleistogamous capsule and seeds various . . . (36)

36(35)a. Margins of largest leaf blades closely pectinately serrate, surfaces glabrous or sparsely appressed-hirtellous; chasmogamous flowers held above the leaves; lowest sepals linear-lanceolate, acuminate; auricles prominent, elongating to 3 mm in fruit; sporadic along Atlantic Coastal Plain . . . Viola pectinata E.P.Bicknell

36(35)b. Margins of largest leaf blades merely crenate to serrate, various in indument; chasmogamous flowers held above or among the leaves; lowest sepals and auricles various; most species absent from or rare on the Atlantic Coastal Plain . . . (37)

37(36)a. Plant in chasmogamous flower . . . (38)

37(36)a. Plant in cleistogamous fruit . . . (60)

38(37)a. Largest leaf blades approx. as broad as long to broader than long (length:width ratio < 1.2), broadly ovate or orbiculate to deltate or reniform . . . (39)

38(37)b. Largest leaf blades distinctly longer than broad (length:width ratio ≥ 1.2) . . . (50)

39(38)a. Spurred petal sparsely to densely bearded within; lower surface of leaf blades commonly purple-tinged (blades uniformly green in Viola pratincola Greene and Viola retusa Greene) . . . (40)

39(38)b. Spurred petal glabrous within; foliage green (foliage blue-green, petioles, midrib on upper surface of leaf blades, lower surface of leaf blades, peduncle, and calyx purple-tinged in Viola sororia [hirsutuloides variant]) . . . (44)

40(39)a. Foliage and peduncle sparsely to densely hirsute, leaf blade margins spreading-ciliate with hairs commonly long; calyx glabrous or appressed-hirtellous, ciliate to apex with hairs commonly long; auricles prominent, quadrate . . . Viola septentrionalis species complex, in part

40(39)b. Foliage and peduncle glabrous or upper surface of leaf blades with small scattered subappressed hairs, blade margins eciliate; calyx glabrous, eciliate; auricles short and rounded or prominent and quadrate . . . (41)

41(40)a. Largest leaf blades broadly ovate, orbiculate or reniform, broadly obtuse to rounded at apex; lowest sepals oblong to ovate, convexly tapering to obtuse to rounded apex; dry or wet calcareous open sites, transcontinental, Northeast, Great Plains, and the West . . . Viola nephrophylla Greene, in part

41(40)b. Largest leaf blades ovate to broadly deltate-triangular, acute to short-acuminate at apex; lowest sepals lanceolate to linear-lanceolate, acuminate from near base or middle to sharply acute apex (oblong-lanceolate to ovate-lanceolate and usually acute in Viola latiuscula Greene) . . . (42)

42(41)a. Petals broadly obovate, broadly rounded; lowest sepals > 2 mm wide, oblong-lanceolate to ovate-lanceolate, acute (occasionally narrowly obtuse); auricles short and rounded; lower surface of leaf blades commonly tinged with purple; summit of petioles commonly papillate, granular, or minutely puberulent; dry sandy woodland soils and dry ledges, northeastern endemic, Vermont to southeastern Ontario, south to Connecticut and New York . . . Viola latiuscula Greene, in part

42(41)b. Petals narrowly to broadly obovate, broadly rounded (Viola pratincola) or upper commonly retuse (Viola retusa); lowest sepals < 2 mm wide, linear-lanceolate to oblong-lanceolate, acuminate from near base or middle to sharply acute apex; auricles prominent, quadrate; leaves uniformly green; petioles smooth; moist to wet soils of wet prairies, bottomlands, and stream- and riverbanks in Great Plains and western Midwest . . . (43)

43(42)a. Largest leaf blades ovate to broadly ovate; petals broadly obovate, broadly rounded; lowest sepals oblong-lanceolate, acuminate from middle to sharply acute apex; wet prairies, stream banks and bottomlands, lawns, and railroad rights-of-way, in western Midwest and eastern Great Plains . . . Viola pratincola Greene, in part

43(42)b. Largest leaf blades ovate or broadly deltate-triangular; petals narrowly obovate, upper commonly retuse; lowest sepals linear-lanceolate to lance-triangular, acuminate from near base to sharply acute apex; gravel alluvium and riparian zones in the Great Plains, North Dakota, and southern Wyoming south to Oklahoma and New Mexico; slightly disjunct in southeastern Minnesota . . . Viola retusa Greene, in part

44(39)a. Lowest sepals oblong to ovate, convexly tapering to obtuse to rounded apex; auricles not prominent, short and rounded or truncate . . . (45)

44(39)b. Lowest sepals linear-lanceolate or oblong-lanceolate to ovate-triangular, acuminate from base or middle to sharply acute apex (convexly tapering to acute apex in Viola domestica); auricles prominent, narrowly linear to trapezoidal (somewhat prominent and truncate in Viola domestica) . . . (47)

45(44)a. Foliage sparsely to densely hirsute; chasmogamous and cleistogamous peduncles sparsely to moderately hirsute; calyx ciliate; widespread in eastern North America westward into the eastern Great Plains . . . Viola sororia sensu stricto, in part

45(44)b. Foliage strictly or essentially glabrous, upper surface of leaf blades in some taxa with scattered small to minute subappressed hairs (petioles occasionally sparsely hirtellous in Viola sororia [hirsutuloides variant]); chasmogamous and cleistogamous peduncles glabrous; calyx eciliate . . . (46)

46(45)a. Foliage, peduncles, and calyx uniformly medium green; apex of leaf blades obtuse or abruptly acutish; margins incurved-serrate or closely serrulate; lowest sepals oblong to narrowly ovate (uncommonly broadly so), obtuse to rounded at apex . . . Viola sororia (glabrous variant), in part

46(45)b. Foliage, peduncle, and calyx blue-green; midrib of upper leaf blade surface, lower surface of leaf blades, petioles, peduncle, and calyx tinged with purple; apex of leaf blades broadly rounded; margins shallowly crenate; lowest sepals ovate, broadly rounded at apex (occasionally narrowly so) . . . Viola sororia (hirsutuloides variant), in part

47(44)a. Corolla pale blue or violet with purple eyespot; lowest sepals linear-lanceolate, acuminate from near base to narrowly sharply acute apex; lateral petal beards very short, exposing throat in living material, hairs (especially those on the perimeter of the beard) strongly clavate or reniform to “doorknob-shaped”; leaf blades narrowly ovate to ovate, narrowly rounded to obtuse at apex, medium to light green, dull on both surfaces in living material; upper leaf blade surface with scattered easily visible appressed hairs; auricles commonly prominent, rectangular, entire; wet soils in marshes, swamps, lakeshores, stream- or riverbanks, and ditches . . . Viola cucullata Aiton, in part

47(44)b. Corolla uniformly violet to purple (white with broad blue, blue-gray, or purple eyespot in Viola communis f. priceana); lowest sepals ovate-triangular, acuminate from middle to sharply acute apex (convexly tapering to acute apex in Viola domestica); lateral petal beards long, obscuring throat in living material, hairs filiform or slightly clavate; leaf blades suborbiculate or deltate-ovate to reniform, broadly rounded to abruptly obtuse-angulate at apex, light to medium or deep green, dull or glossy on both surfaces in living material; foliage glabrous or upper leaf blade surface with scattered minute appressed hairs requiring magnification; auricles weakly prominent, trapezoidal, and commonly erose or quadrate and truncate; native to moist loamy soils in floodplains and bottomlands, often spreading or persisting in moist lawns in the eastern states, adventive or planted in suburbs and cities west of Kentucky and Ohio in Viola communis) or almost exclusively cultivated (Viola domestica) . . . (48)

48(47)a. Foliage light to medium green with upper leaf blade surfaces scarcely glossy to dull in living material; largest leaf blades broadly ovate to reniform, margins somewhat coarsely crenate-serrate, angulate to obtuse or broadly acute apex; lowest sepals oblong-lanceolate, convexly tapering to acute apex; cultivated, perhaps barely escaping . . . Viola domestica E.P.Bicknell, in part

48(47)b. Foliage deep green, occasionally with basal half of petioles and peduncles purple-tinged, with upper leaf blade surfaces glossy; largest leaf blades suborbiculate to deltate-ovate, margins closely and uniformly crenate-serrate; lowest sepals ovate-triangular, acuminate from middle to sharply acute apex; native to stream terraces, ecotones between mesic forest slopes and floodplains, and often escaping into lawns, mostly central and eastern USA, cultivated and escaped west of Kentucky and Ohio . . . (49)

49(48)a. Corolla violet to purple, lacking a conspicuously contrasting eyespot . . . Viola communis Pollard f. communis

49(48)b. Corolla white with broad blue, blue-gray, or purple eyespot . . . Viola communis Pollard f. priceana (Pollard) H.E.Ballard

50(38)a. Spurred petal sparsely to densely bearded within . . . (51)

50(38)b. Spurred petal glabrous within . . . (57)

51(50)a. Foliage sparsely to densely hirsute; lowest sepals oblong to ovate, convexly tapering to narrowly or broadly rounded apex; calyx eciliate or cili(ol)ate . . . (52)

51(50)b. Foliage glabrous, or upper surface of leaf blades bearing small, scattered, subappressed hairs (foliage occasionally sparsely to moderately hirtellous in Viola sagittata); lowest sepals linear- to oblong-lanceolate or lance-triangular, acuminate from near base or middle to sharply acute apex; calyx eciliate . . . (54)

52(51)a. Largest leaf blades narrowly ovate, convexly tapering to narrowly rounded or acute apex, margins commonly ciliate with long hairs; sepals ciliate nearly or fully to apex with commonly long hairs; dry to moist woodlands, often associated with limestone or igneous rock outcrops, boreal, interruptedly transcontinental, primarily boreal, Appalachian, Northeast, Upper Midwest, and northern Rocky Mountains, Newfoundland and Labrador to Saskatchewan and British Columbia, south to western North Carolina and eastern Tennessee; eastern Iowa, western Montana, and eastern Washington . . . Viola septentrionalis species complex, in part

52(51)b. Largest leaf blades narrowly ovate-triangular, convexly tapering or acuminate from near base to sharply acute apex, margins sparsely to moderately ciliate with short hairs; various habitats, almost strictly boreal . . . (53)

53(52)a. Leaves and peduncles moderately to densely hirsute; margins of leaf blades with 10–(avg. 14)–21 teeth on each side, ciliate; calyx often pubescent, margins uniformly ciliate (often with long hairs) to apex; lowest sepals 2.7–3.8 mm wide, length:width ratio ≤ 2.1; western Great Lakes region, northern Michigan to southeastern Manitoba, south to central Wisconsin and central Minnesota, disjunct in Hastings Co. in southeastern Ontario . . . Viola grisea (Fernald) H.E.Ballard, in part

53(52)b. Petioles glabrous or sparsely hirsute below middle, leaf blades and peduncles glabrous; margins of leaf blades with 10–(avg. 11)–14 teeth on each side, eciliate; calyx glabrous, eciliate; lowest sepals 1.9–2.7 mm wide, length:width ratio > 2.1; Maine and New Brunswick, disjunct in eastern New York . . . Viola novae-angliae House, in part

54(51)a. Largest leaf blades narrowly elliptical, ovate-lanceolate, lance-triangular, or sagittate; base narrowly (sub)cordate; foliage glabrous or sparsely to moderately hirtellous; flowers overtopping leaves; auricles prominent and quadrate; in dry to moist sand of sand barrens and dry prairies, and lakeshores . . . Viola sagittata Aiton, in part

54(51)b. Largest leaf blades narrowly ovate- to deltate-triangular; foliage glabrous or upper surface of leaf blades bearing scattered, small, subappressed hairs; flowers held among the leaves; auricles short and rounded (Viola affinis) or prominent (Viola pratincola and Viola retusa); in sandy, silty or muck soils of floodplains, drainages, and swamps, or in gravel or sand along riverbanks . . . (55)

55(54)a. Largest leaf blades narrowly ovate-triangular; upper surface of leaf blades bearing scattered, small, subappressed hairs; upper petals broadly obovate, broadly rounded; auricles short and rounded; spurred petal densely bearded; stream and river terraces, floodplains, and swamps, widely distributed, mostly east of the Mississippi River . . . Viola affinis Leconte, in part

55(54)b. Largest leaf blades narrowly ovate to narrowly deltate-triangular; leaves glabrous; upper petals narrowly or broadly obovate, broadly rounded or retuse; auricles typically prominent, quadrate; spurred petal sparsely to densely bearded; riverbanks, riparian wet prairies, bottomlands, Wisconsin and Illinois westward . . . (56)

56(55)a. Largest leaf blades narrowly ovate to ovate, acute at apex; petals broadly obovate, broadly rounded; lowest sepals oblong-lanceolate, acuminate from middle to sharply acute apex; spurred petal sparsely bearded; wet prairies, terraces bordering streams and rivers, and streambanks in swampy woods, often invading (or persisting in) low-lying lawns, railroad rights-of-way, and other anthropogenic sites . . . Viola pratincola Greene, in part

56(55)b. Largest leaf blades narrowly deltate-ovate or deltate-triangular, shortly acuminate at apex; petals narrowly obovate, upper commonly retuse; lowest sepals linear-lanceolate to lance-triangular, acuminate from near base to sharply acute apex; spurred petal densely bearded; gravel and sand alluvium along rivers in the Great Plains, North Dakota, and southern Wyoming south to Oklahoma and New Mexico; slightly disjunct in southeastern Minnesota . . . Viola retusa Greene, in part

57(50)a. Calyx ciliolate (populations in Upper Midwest commonly eciliate); lowest sepals oblong to ovate-lanceolate, gradually or abruptly tapering to a narrowly obtuse to rounded apex; auricles short and rounded . . . Viola missouriensis Greene, in part

57(50)b. Calyx eciliate (some northern populations of Viola cucullata with sparsely ciliate margins); lowest sepals linear-lanceolate to ovate-triangular, acuminate from near base or middle to sharply acute apex; auricles prominent to elongate . . . (58)

58(57)a. Corolla pale blue or violet with purple eyespot; lowest sepals linear-lanceolate; lateral petal beards very short, with strongly clavate to reniform hairs; widely distributed over eastern North America, mostly absent on the southeastern Atlantic and Gulf Coastal Plains . . . Viola cucullata Aiton, in part

58(57)b. Corolla violet, lacking purple eyespot but with flush of dark purple at base of lateral petals; lowest sepals lance- to ovate-triangular; lateral petal beards long, with slightly clavate hairs; southern Atlantic and Gulf Coastal Plains . . . (59)

59(58)a. Leaves strongly ascending in living material; petioles, lower surface of leaf blades, peduncle, and calyx commonly tinged or finely spotted with purple; auricles prominent to very elongate, 1.5–4 mm long; frequently flooded sandy and silty soils along streams and rivers on the southern lower Atlantic Coastal Plain, North Carolina south to southeastern Georgia (not yet documented in our region, see “Potential Taxa”) . . . Viola “impostor”, in part

59(58)b. Leaves widely spreading in living material; foliage, peduncle, and calyx green; auricles prominent, to ≤ 1.5 mm long; Gulf Coastal Plain, eastern Texas to western Florida panhandle, north to southeastern Missouri (not yet documented in our region, see “Potential Taxa”) . . . Viola langloisii Greene, in part

60(37)a. Largest leaf blades substantially longer than broad (length:width ratio ≥ 1.2), lance-triangular or sagittate to narrowly ovate-triangular . . . (61)

60(37)b. Largest leaf blades about as long as broad to broader than long (length:width ratio < 1.2), broadly ovate or broadly deltate-triangular to reniform . . . (63)

61(60)a. Leaf blades lance-triangular or sagittate; foliage glabrous or sparsely to moderately hirtellous; peduncle glabrous; cleistogamous capsule unspotted, on erect peduncle; calyx eciliate; sepals lanceolate to lance-triangular, acuminate; auricles elongating to 3 mm or more; distributed almost exclusively south of the boreal region . . . Viola sagittata Aiton, in part

61(60)b. Leaf blades narrowly ovate-triangular; foliage glabrate or sparsely to densely hirsute; peduncle glabrous or hirsute; cleistogamous capsule heavily purple-spotted or blotched, on prostrate peduncle arching upward just prior to dehiscence; calyx eciliate or ciliate; sepals oblong to ovate, narrowly to broadly rounded; auricles weakly elongating to 2 mm; confined to the boreal region . . . (62)

62(61)a. Petioles and lower surface of leaf blades moderately to densely hirsute; peduncle hirsute; margins of leaf blades with 10–(avg. 14)–21 teeth on each side, ciliate; calyx often pubescent, margins uniformly ciliate (often with long hairs) to apex; sepals 2.7–3.8 mm wide, length:width ratio ≤ 2.1; Western Great Lakes region, northern Michigan to southeastern Manitoba, south to central Wisconsin and central Minnesota, disjunct in Hastings Co. in southestern Ontario . . . Viola grisea (Fernald) H.E.Ballard, in part

62(61)b. Petioles glabrous or sparsely hirsute below middle, leaf blades glabrous; peduncle glabrous; margins of leaf blades with 10–(avg. 11)–14 teeth on each side, eciliate; calyx glabrous, eciliate; sepals 1.9–2.7 mm wide, length:width ratio > 2.1; Maine and New Brunswick, disjunct in eastern New York . . . Viola novae-angliae House, in part

63(60)a. Petioles and lower surface of leaf blades hirsute; peduncle hirsute; calyx ciliate . . . (64)

63(60)b. Foliage glabrous or upper surface of leaf blades with scattered small to minute subappressed hairs (petioles occasionally sparsely hirtellous in Viola sororia [hirsutuloides variant]); peduncle glabrous; calyx eciliate (ciliolate in Viola missouriensis) . . . (66)

64(63)a. Margins of leaf blades ciliate with short ascending hairs; sepals ciliate in proximal 1/2(2/3) with short hairs; auricles short and rounded; seeds 1.5–2.6 × 0.9–1.6 mm, dark gray to dark grayish-brown or blackish, unspotted or with small usually weak blackish streaks; inhabiting drier to moist loamy, sandy, or clayey soils in upland and lowland forests in much of eastern North America . . . Viola sororia sensu stricto, in part

64(63)b. Margins of leaf blades ciliate with spreading often long hairs; sepals ciliate to apex, cilia often long; auricles prominent, quadrate and/or erose, elongate to 2 mm; seeds 1.2–2.3 × 0.8–1.2 mm, light-medium brown to dark brown, unspotted or with small weak darker streaks or spots; inhabiting limestone and dolomite-associated soils in the boreal region of northern North America and southward at higher elevations into the southern Appalachian Mountains, igneous rocks and acidic soils in the Upper Midwest . . . (65)

65(64)a. Foliage sparsely to densely hirsute; sepals ovate-triangular and acuminate from middle to oblong-ovate or ovate and obtuse to rounded, sparsely to densely ciliate; seeds 1.2–2.3×0.8–1.2 mm, narrowly obovoid, light-medium brown to dark brown, unspotted; in dryish to moist forests, commonly on or near limestone, across boreal Canada, south into the northwestern Rocky Mountains and New England and at higher elevations into the southern Appalachian Mountains . . . Viola septentrionalis sensu stricto

65(64)b. Foliage uniformly densely hirsute; sepals ovate and obtuse to rounded, uniformly densely ciliate; seeds 1.9–2.1 × 1.2–1.3 mm, broadly obovoid, red-brown, with small weak darker streaks or darker raised spots; on or near igneous outcrops in Thunder Bay area, Ontario, south to Minnesota and eastern Iowa . . . Viola septentrionalis (Upper Midwest variant)

66(63)a. Capsule unspotted . . . (67)

66(63)b. Capsule finely spotted, or heavily purple-spotted or blotched . . . (73)

67(66)a. Peduncle declined . . . (68)

67(66)b. Peduncle ascending to erect (initially prostrate and coiled then elongating to become sinuous-erect in Viola communis, arching to ascending in Viola domestica) . . . (69)

68(67)a. Petioles and leaves widely spreading in living material; leaf blades deltate-triangular, broadly acute or right-angled at apex; sepals lanceolate, acuminate; auricles prominent, elongating to 2 mm; seeds yellow-brown, unspotted; silt or sand in floodplains of streams and rivers in Gulf Coast region and Florida, north to southeastern Missouri (not yet documented in our region, see “Potential Taxa”) . . . Viola langloisii Greene, in part

68(67)b. Petioles ascending in living material; leaf blades reniform, broadly obtuse to rounded at apex; sepals oblong to ovate, obtuse to rounded; auricles short and rounded; seeds medium brown to dark olive-brown, unspotted or rarely with minute raised darker spots; dry or wet calcareous open sites, transcontinental, Northeast, Great Plains, and the West . . . Viola nephrophylla Greene, in part

69(67)a. Cleistogamous peduncle relatively short, ascending to erect or eventually arching to sinuous-erect, not reaching petioles; sepals oblong- to ovate-lanceolate or ovate-triangular, < 1/2 as long as the capsule, convexly tapering to an acute apex or acuminate from the middle to a sharply acute apex; auricles weakly elongate; seeds medium brown or olive- to brownish-black or blackish, with minute raised black spots; ecotonal thickets, stream terraces and floodplains (Viola communis), wet prairies, and streambanks in swampy woods (Viola pratincola), and escaping into lawns or railroad rights-of-way, or cultivated and perhaps barely escaping (Viola domestica) . . . (70)

69(67)b. Cleistogamous peduncle tall and erect, often reaching or surpassing petioles; sepals linear-lanceolate to lanceolate, > 1/2 as long as the capsule, acuminate from near base to a sharply acute apex; auricles weakly or strongly elongate; seeds medium to dark brown or reddish-brown, unspotted or spotted; intermittently or permanently wet soils of wetlands, swamps, and riverbanks, not cultivated or escaping to lawns and other anthropogenic sites . . . (72)

70(69)a. Foliage glabrous except for upper surface of leaf blades with scattered minute appressed hairs requiring magnification; largest leaf blades suborbiculate to deltate-reniform, base shallowly to deeply cordate and not noticeably cuneate-decurrent onto summit of petiole, apex broadly obtuse to rounded, both surfaces glossy in living material, margins closely and uniformly crenate-serrate; peduncle initially prostrate and coiled but eventually becoming sinuous-erect; sepals ovate-triangular, acuminate from middle to sharply acute apex; auricles trapezoidal, commonly erose; in moist clay or loam soils of thickets, grassy banks and meadows, slope-floodplain transitions, floodplains, lawns, roadsides, and suburban woodlots . . . Viola communis Pollard, in part

70(69)b. Foliage glabrous; largest leaf blades broadly deltate-ovate to deltate-reniform, base shallowly cordate or subtruncate and shortly cuneate-decurrent onto summit of petiole, apex broadly and abruptly obtuse-angulate to subacuminate, both surfaces dull or upper surface scarcely glossy in living material, margins conspicuously incurved-crenate-serrate; peduncle arching or ascending; sepals oblong-lanceolate and convexly tapering to acute apex (Viola domestica) or ovate-lanceolate and acuminate from the middle to a sharply acute apex, < 1/2 as long as capsule; auricles quadrate, truncate . . . (71)

71(70)a. Largest leaf blades broadly deltate-reniform, base subtruncate and shortly cuneate-decurrent onto summit of petiole, apex broadly and abruptly obtuse-angulate, both surfaces dull or upper surface scarcely glossy in living material; peduncle arching or ascending; sepals oblong-lanceolate, convexly tapering to acute apex; seeds 1.9–(avg. 2.0)–2.2 × 1.2–(avg. 1.26)–1.3 mm; planted, possibly rarely escaping . . . Viola domestica E.P.Bicknell, in part

71(70)b. Largest leaf blades deltate-ovate, base cordate and not noticeably decurrent onto summit of petiole, apex abruptly acute to subacuminate, both surfaces dull; peduncle ascending; sepals ovate-lanceolate, acuminate from middle to a sharply acute apex; seeds 1.4–(avg. 1.8)–2.1 × 0.8–(avg. 1.1)–1.3 mm; wet prairies, stream banks and bottomlands, lawns, and railroad rights-of-way, in western Midwest and eastern Great Plains . . . Viola pratincola Greene, in part

72(69)a. Auricles strongly elongate, 3–8 mm; seeds 1.4–1.9 × 0.8–1.3 mm, dark brown to dark reddish-brown, unspotted; open or forested wet sites including marshes, sedge meadows, seeps, bog forests, and swamps throughout most of eastern North America, mostly east of the Great Plains . . . Viola cucullata Aiton, in part

72(69)b. Auricles weakly elongate to 1.5(–2) mm; seeds 1.7–2.2 × 1.0–1.3 mm, medium brown with dense minute raised black spots; gravel and sand alluvium along streams and rivers in the Great Plains, North Dakota, and southern Wyoming south to Oklahoma and New Mexico; slightly disjunct in southeastern Minnesota . . . Viola retusa Greene, in part

73(66)a. Sepals oblong- to ovate-lanceolate or ovate, convexly tapering to a narrowly or broadly obtuse to rounded apex . . . (74)

73(66)b. Sepals linear-lanceolate to ovate-triangular, acuminate (acute to narrowly rounded in Viola latiuscula) . . . (76)

74(73)a. Calyx ciliolate; seeds 1.5–2.2 × 1.0–1.3 mm, medium orange-brown, unspotted or with small weak darker streaks, blotches, and spots; sandy or silty soils of bottomland forests, in western Midwest, Lower Midwest, and Great Plains . . . Viola missouriensis Greene, in part

74(73)b. Calyx eciliate; seeds 1.5–2.0 × 1.0–1.3 mm (limited measurements, upper ranges may be larger), light to medium gray or gray-brown with small prominent gray or gray-brown streaks (seeds of Viola sororia [hirsutuloides variant] unknown); various substrates, especially in rich mesic upland forests, in the Appalachian Mountains and associated uplands . . . (75)

75(74)a. Foliage, peduncles, and calyx uniformly medium green; largest leaf blades deltate-reniform, base cordate to subcordate, apex obtuse or abruptly acutish; margins incurved-serrate or closely serrulate; sepals oblong to narrowly ovate (uncommonly broadly so), obtuse to rounded at apex . . . Viola sororia (glabrous variant), in part

75(74)b. Foliage, peduncles, and calyx blue-green, midrib of upper leaf blade surface often purple, lower surface of leaf blades, petioles, peduncles, and calyx tinged with purple; largest leaf blades broadly ovate to reniform, base deeply cordate, apex broadly rounded or apiculate; margins shallowly crenate; sepals ovate, narrowly to broadly rounded at apex . . . Viola sororia (hirsutuloides variant), in part

76(73)a. Peduncle declined, or initially prostrate and coiled but becoming erect-sinuous; auricles prominent, weakly to strongly elongate, 1.5–4 mm; seeds olive-brown or brownish-black to black, unspotted or with minute black spots . . . (77)

76(73)b. Peduncle initially prostrate, arching upward prior to capsule dehiscence; auricles short and rounded or truncate; seeds yellow- to orange-brown or purple-black and unspotted, or light red-brown with dark brown or red-brown blotches . . . (78)

77(76)a. Largest leaf blades broadly obtuse to rounded at apex, both surfaces glossy in living material; peduncle stout, initially prostrate and coiled, elongating to become erect-sinuous prior to dehiscence; calyx green; auricles triangular-trapezoidal, weakly elongate to 1.5(2) mm; capsule finely spotted to heavily blotched with dark purple; seeds 1.5–2.5 × 0.9–1.5 mm, olive-brown, brownish-black to black with dense minute raised spots or rarely unspotted; in moist clay or loam soils of thickets, grassy banks and meadows, slope-floodplain transitions, floodplains, lawns, roadsides, and suburban woodlots, widespread in eastern North America, rare on the Atlantic Coastal Plain, populations west of Ohio and Kentucky planted and escaped . . . Viola communis Pollard, in part

77(76)b. Largest leaf blades (abruptly) acute at apex, neither surface glossy in living material; peduncle slender, declined or ascending from the beginning, gently curved; calyx purple-pigmented (rarely green); auricles narrowly linear, strongly elongate, (1.5)2–4 mm; capsule finely purple-spotted at least at base; seeds 1.3–1.8 × 0.9–1.2 mm, dark brown with white raphe, unspotted; frequently flooded sandy and silty soils along streams and rivers on the southern lower Atlantic Coastal Plain, North Carolina south to southeast Georgia (not yet documented in our region, see “Potential Taxa”) Viola “impostor,” in part

78(76)a. Largest leaf blades approx. as broad as long, ovate- to deltate-triangular, 37–69 mm wide, broadly acute at apex, shallowly to moderately cordate at base; petioles smooth throughout; sepals linear-lanceolate or lanceolate, acuminate, ≥ 1/2 as long as mature or dehisced cleistogamous capsule; cleistogamous capsules frequently hirtellous; seeds light to medium yellow- or orange-brown, unspotted; moist to wet soils of swamps, floodplains, and riverside meadows over much of eastern North America east of the Great Plains, mostly absent from the central and southern Atlantic Coastal Plain, absent from the Gulf Coastal Plain . . . Viola affinis Leconte, in part

78(76)b. Largest leaf blades much broader than long, broadly deltate-reniform, 34–145 mm wide, abruptly obtuse to acute at apex, truncate to subcordate at base; summit of petioles granular or papillate-puberulent; sepals oblong-lanceolate to ovate-lanceolate, acute or acutish, mostly < 1/2 as long as mature or dehisced cleistogamous capsule; cleistogamous capsules glabrous; seeds purplish-black, with very weak darker blotches, spots, or streaks; dry sandy soils in upland forests or dry ledges, northeastern endemic, Northeastern endemic, Vermont to southeastern Ontario, south to Connecticut and New York . . . Viola latiuscula Greene, in part

由使用者 rynxs rynxs2023年04月27日 06:40 所貼文

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