Cheilanthes horridula
Cheilanthes horridula Maxon
(Latin: horridus, prickly, bristly, or rough, in reference to the stiff hairs on the upper leaf surfaces)
Local names: rough lip fern, prickly lip fern
Rhizomes short-creeping; leaves clustered, 5–30 cm long; petioles black to dark brown, rounded on upper surface; leaf blades oblong-lanceolate, 1–4 cm wide, 1-pinnate- pinnatifid to 2-pinnate-pinnatifid at base, pinnae not articulate, the ultimate segments narrowly elliptic to elongate-deltate, not bead-like, the largest 3–5 mm long, scabrous on both upper and lower surfaces due to distinctive stiff hairs, these often inflated basally; scales on underside of costae lanceolate, not conspicuous compared to those of some Cheilanthes species; 2n = 58, 116 (Windham & Rabe 1993). Rock crevices, rocky slopes, and ledges, typically on limestone; mainly Edwards Plateau (e.g., Real Co., J.L. Blassingame 2906, BRIT) and Trans-Pecos, but scattered in adjacent areas; in the U.S. primarily in TX but also in extreme s OK (Murray Co.); also n Mexico. Sporulating mainly May–Nov. According to Windham and Rabe (1993), the scabrous pustulose hairs make this “one of the most distinctive species of Cheilanthes in North America.” It includes both sexually reproducing diploids and tetraploids and needs further study. This is the only member of Cheilanthes that has its leaf surfaces roughened by distinctive stiff, prickly, basally inflated hairs.