rem267 的鑑定

The more I look at Ferns, the less they all look alike. This turns out to be yet another species new to me as a newly more Fern conscious observer.

In this specimen, growing with a couple other species (Christmas Fern, also perennial, among them), had fertile fronds that were very like the non-fertile fronds, and the round spore producing areas, known as sori, were sort of randomly distributed along the outer edges (hence the term "marginal") of the leaflets, from 1 to 4 per sub-leaflet. The leaflets themselves were gently curved toward the distal tip of the frond.

Not knowing this new species' characteristics at the time in the field, I did not know what to look for or photograph. In retrospect, it seems this specimen did not well display the radial structure the fronds have from a central rootstock, probably because it was on a steep shifting rocky slope. I found another specimen nearby that at first seemed to have a different pattern of sori underneath, which I will post separately (see: https://www.inaturalist.org/observations/200095222) for comparison.

This stretch of Enlow Fork has carved a lot of north facing quite steep slopes, in a deep narrow East-West oriented valley, so there is a large area of damp shady woodland environment for Ferns, Mosses, and the like. The underlying rock here in southwestern Pennsylvania, is mostly thinly bedded sandstones and shales that break up quite easily, so are not much exposed at the surface, and contain very little limestone. This greatly effects the soil composition and vegetation in these mixed deciduous woods. There are places one can glimpse those geological underpinnings, in these steep sided valleys and at roadcuts. The elevation at this location, low down on the shady valley wall, was around 275 meters (902 feet).