Asplenium trichomanes
Asplenium trichomanes L. subsp. trichomanes
(Greek: thrix, trichos, hair, and manes, a kind of cup, = hairy cup, and also the ancient Greek name for a fern that may have been in some way similar; before Linnaeus, botanists placed this species in the unrelated genus Trichomanes—Thieret 1980)
Local names: maidenhair spleenwort
Rhizomes short-creeping, sometimes branched; leaves monomorphic, usually to only 25 cm tall; leaf bladeslinear to narrowly linear-oblong in outline; petiole and rachis reddish brown or blackish brown, shiny; pinnae subopposite to alternate, oval to broadly oblong (somewhat rounded in appearance), usually less than 2 times as long as wide, the medial ones 8 mm or less long, minutely crenulate to serrulate to subentire; 2n = 72 (Wagneret al. 1993 for subsp. trichomanes). In sheltered crevices of cliffs and ledges on noncalcareous rocks; in TXknown only from Sawtooth Mt. (Correll 15005, TEX-LL) and Mt. Livermore (Yarborough & Powell 2002) in the Davis Mts. of Jeff Davis Co. and also in Glass Mts. of Brewster Co. (Warnock 19069, SRSC; Turner et al. 2003); widespread in the e . of the U.S. and scattered in the w . of the country; also se and w Canada, n Mexico (Chihuahua), Asia, Europe, Africa, and Australia. Sporulating Mar–Oct. [A. melanocaulon Willd.] Correll (1956) noted that the “small roundish pinnae distinguishes this species from the other Aspleniums found in Texas.” The plants in TX are subsp. trichomanes; three other subspecies are recognized as occurring elsewhere in the world, these sometimes differing in chromosome number and habitat; for example, subsp. quadrivalens D.E. Mey., which occurs in the n U.S., is tetraploid and occurs on calcareous rocks (Wagner etal. 1993). Correll’s collection from Sawtooth Mt. noted that the plant was “Very rare!” Given its rareness and limited distribution in the state, we consider this species to be of conservation concern in TX.