| Author | Willdenow | |
| Distribution | Throughout the Mountains; present at most of the western Piedmont ranges and isolated monadnocks, but widely scattered only eastward in that province, extending to Durham and Harnett counties (Raven Rock SP).
This is primarily an Appalachian species, ranging from MA and NY southwest to central GA, central AL, and rarely in AR. | |
| Abundance | Frequent to common in the mountains (but only within its restricted habitat); infrequent in the western Piedmont, but very rare in the central and eastern Piedmont. | |
| Habitat | This is a rock inhabitant, growing mainly in cracks and crevices of felsic rocks -- mostly metamorphic and sedimentary ones such as gneisses, schists, sandstone, and granite. At times it may occur on mafic rocks such as amphibolite, but it does not grow on calcareous rocks such as limestone. It can occur in both moist, shaded crevices as well as sites that are dry and more exposed. |
| Phenology | Fruits from May to September. | |
| Identification | This is the most frequent of the small, rock-inhabiting ferns in the state, not limited to limestone or other similar calcareous sites as so many others are. Numerous fronds occur in a clump, with the stipe only about 2 inches long, dark brown at the base but green in the upper portion, and continuing green as the rachis in the blade. The blade is narrowly triangular, about 5-6 inches long and 2 inches wide at the base, with the lower pinnae mostly bipinnate-pinnatifid and upper ones only pinnate-pinnatifid. There are only 5-12 pairs of pinnae, alternate on the rachis; the lowest pinna is the largest/longest, with the ones above reduced in length toward the apex of the blade. There are several short sori under each pinnule, arranged diagonally to the midrib. The overall effect is of a rather lacy-cut fern with a rather short blade that is clearly triangular in shape. The main identification contender is A. bradleyi, which has a narrower blade (almost oblong in shape) and the entire stipe -- to the lowest pinnae -- is shiny brown. | |
| Taxonomic Comments | None
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| Other Common Name(s) | None | |
| State Rank | S4 | |
| Global Rank | G5 | |
| State Status | | |
| US Status | | |
| USACE-agcp | | |
| USACE-emp | | |
