The cliffs of the Octoraro, redux

I really do visit other places, I promise. Back in September, acting on a tip from a botanical mentor, I revisited the cliffs of the Octoraro to look for walking fern again.

The name "cliff" is reasonably well-deserved. Though they're covered in oak forest, the slopes down to the Octoraro are very steep indeed, with rock outcrops and talus poking through the soil here and there. Sadly, the understory is thickly overgrown with stiltgrass. But a number of herbs continue to struggle gamely through the stiltgrass cover. What remains of the vegetation described in Pennell's classic article?

I didn't visit the high ridges that host the Goat Hill chickweed; it's still up there in a nearly impenetrable fortress of greenbrier. Pennell assigns three other species to the cliffs: "There in rock-crevices grows luxuriantly the harebell, Campanula rotundifolia, mingled with the equally northern snowy bedstraw, Galium boreale. The Canada lettuce, true Lactuca canadensis with the mid-blade and segments of the leaves linear and entire, further emphasizes the northern affinity of the flora of these cliffs. But Aster concinnus, with greener leaves and more ample sprays of smaller flowerheads than has A. laevis, its close kin elsewhere on the Serpentine, is of very local occurrence and has been little found anywhere in its range."

The harebell, though not abundant, still festoons the cliffs, together with quantities of wild columbine (Aquilegia candensis). I didn't see Galium boreale on the cliffs, but I run across it in rocky grasslands: at Goat Hill, Nottingham, and in a little barrens in Harford County, often quite abundant.

And this time, with slightly better directions, I found the walking fern! Asplenium rhizophyllum is growing, as is its wont, on moss-covered boulders, albeit of serpentine, not limestone. The colony is quite large. I took a number of pictures, and even found a place or two where ebony spleenwort, A. platyneuron is growing in juxtaposition to the walking fern. Alas, no hybrids were to be found. Nonetheless, it's always a good day when you find walking fern off of a calcareous substrate.

由使用者 choess 在 2018年05月21日 05:29 所貼文