Cheilanthes aemula
Cheilanthes aemula Maxon
(Latin: aemula, rival, emulating or imitating, probably because at the type locality it was growing with, and was initially confused with C. microphylla, a species widespread in Latin America)
Local names: Texas lip fern, rival lip fern
Rhizomes short-creeping; leaves clustered, 10–50 cm long; petioles dark brown to black, rounded on upper surface; leaf blades broadly triangular to ovate, 5–15 cm wide, 3-pinnate to 3-pinnatepinnatifid basally, the pinnae not articulate, the largest ultimate segments 3–6 mm long, not bead-like, with sparse hairs or glabrous on lower (unusual in that most other species except C. alabamensis and C. fendleri are hairy) and upper surfaces; costae without scales on lower surfaces; rachises similar to those in C. alabamensis; 2n = 58 (Windham & Rabe 1993). Rocky slopes and ledges, on limestone; Austin Co. in se Blackland Prairie (Correll 1956; Turner et al. 2003), Val Verde (e of the Pecos—Turner et al. 2003), BRIT), Comal, and Uvalde (TEX-LL) cos. on the Edwards Plateau, Val Verde (Correll & Correll 12910, BRIT, TEX-LL, D. Flyr 739, TEXLL, both w of Pecos River), Big Bend State Park near border of Brewster and Presidio (Yarborough & Powell 2002) cos. in the Trans-Pecos, and Starr Co. (R. Runyon 2914, TEX-LL) in far s TX; in the U.S. known only from TX; also n Mexico. Sporulating May–Nov. This species, which is similar to C. alabamensis, is known in the U.S. from only a few localities in e, c, and w TX (Windham & Rabe 1993). Because of its rareness and limited distribution in the state, we consider this species to be of conservation concern in TX.