Taylor's filmy fern

Plants on rock. Leaves (single juvenile specimen known less than 1 cm), with prominent stellate hairs on midrib and margins. Gametophyte gemmae platelike, abundant.

On rock in deeply shaded, moist crevices in narrow gorges and behind waterfalls; 350--1200 m; Ala., N.C., S.C.

This species is described from gametophyte plants. A juvenile sporophyte collected in 1936 by M. S. Taylor is presumed to be this species. * It consists of a short stem with 4 leaves, the largest of which is less than 1 cm. The plant lacks mature characteristics including sori, but the leaves bear stellate hairs typical of subg. Leptocionium sect. Sphaerocionium of C. V. Morton (1968). Gametophytes collected with the sporophyte occur commonly in the area and differ from those of H . tunbrigense both morphologically, especially in bearing copious gemmae, and in enzyme electrophoretic patterns. Therefore, they are here considered to be a distinct species, H . tayloriae (C. A. Raine et al. 1991).

D. B. Lellinger (1985) and G. R. Proctor (1985) have considered the South Carolina sporophyte to be Hymenophyllum hirsutum (Linnaeus) Swartz. Although the characters of the single sporophyte do not exclude this possibility, they are insufficient to permit definite assignment of the plant to this species. Furthermore, adaptations of the gametophytes to independent existence in temperate habitats of the southern Appalachian Mountains suggest genetic differentiation sufficient to warrant species recognition.

* As this volume goes to press, additional juvenile sporophytes identical to those collected by Taylor were found growing with gametophytes of H . tayloriae in Lawrence County, Alabama.