Cheilanthes leucopoda

Stems compact, usually 4--10 mm diam.; scales uniformly brown, linear-subulate, straight to slightly contorted, loosely appressed, persistent. Leaves clustered, 7--30 cm; vernation circinate. Petiole straw-colored, shallowly grooved distally on adaxial surface. Blade elongate-pentagonal, 4-pinnate at base, 3--10 cm wide; rachis grooved adaxially, lacking scales, with monomorphic pubescence. Pinnae not articulate, color of stalk continuing into pinna base, basal pair larger than adjacent pair, strongly inequilateral, proximal basiscopic pinnules greatly enlarged, appearing hirsute adaxially. Costae green or straw-colored adaxially for entire length; abaxial scales absent. Ultimate segments oblong to lanceolate, not especially beadlike, the largest 3--5 mm, abaxially and adaxially hirsute with long, noncapitate hairs. False indusia marginal, weakly differentiated, 0.05--0.25 mm wide. Sori usually discontinuous, concentrated on apical and lateral lobes. Sporangia containing 32 spores. 2 n = 60.

Sporulating summer--fall. Rocky slopes and ledges; apparently confined to limestone; 300--500 m; Tex.; n Mexico.

In North America, Cheilanthes leucopoda is known only from the Edwards Plateau in west central Texas. It is unique among local Cheilanthes species in being a sexual diploid that consistently produces 32 spores per sporangium.