Cystopteris reevesiana

Cystopteris reevesiana Lellinger
(for Dr. Timothy Reeves, 1947–, student and collector of U.S. and Mexican ferns, especially Cheilanthes)

Local names: southwestern brittle fern, brittle fern

Terrestrial or on rocks; rhizomes no protruding beyond attachment of leaves, with internodes relatively long, with tan to brown scales but without hairs; leaves clustered at rhizome tips, monomorphic, to 45 cm long; petioles variable in color, but usually dark purple at least at base and sometimes throughout; rachis and costae without glandular hairs (except for occasional gland-tipped hairs in axils of pinnae) or bulblets; leaf blades finely dissected, 2–3-pinnate to 2–3-pinnate-pinnatifid, ovate to elliptic, widest at or just below middle, apically short attenuate, the ultimate segments crenate to dentate; indusia without glandular hairs; 2n = 84 (Haufler et al. 1993). On rocks (a variety of substrates including limestone or igneous materials) or sometimes terrestrial; Culberson Co. in Guadalupe Mts. (M.S. Young s.n. 1916, TEX-LL), Edwards Co. (Punkin Cave, Schindel s.n., 2007, BRIT—identification confirmed D.B. & J.S. Lellinger in 2007; Cory 35636, in Devil’s Sink Hole, 80 feet below surface, TAES, TEXLL), and Jeff Davis Co. in Madera Canyon, Mt. Livermore, Davis Mts. (Hinckley s.n., 1935, TEX-LL); AZ, CO, NM, TX, and UT; endemic to the U.S.—not known from Mexico despite earlier erroneous reports of its occurrence there (Mickel & Smith 2004). Sporulating summer–fall. [C. fragilis (L.) Berhn. subsp. Tenuifolia Clute] This species can sometimes cross with C. utahensis, producing “sterile triploids of intermediate morphology” (Haufler et al. 1993). Because of its limited distribution in the state, we consider this species to be of conservation concern in TX.

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