Gaga arizonica

Stems short-creeping, usually 4--8 mm diam.; scales uniformly dark brown or with poorly defined, dark, central stripe, narrowly lanceolate, straight to slightly contorted, loosely appressed, usually persistent. Leaves clustered, 8--25 cm; vernation circinate. Petiole dark brown, grooved most of length adaxially. Blade elongate-pentagonal, 3-pinnate-pinnatifid to 4-pinnate at base, 4--10 cm wide; rachis grooved adaxially, lacking scales, with minute, widely scattered hairs. Pinnae not articulate, dark color of stalk continuing into pinna base, basal pair conspicuously larger than adjacent pair, inequilateral, proximal basiscopic pinnules enlarged, glabrous adaxially. Costae green adaxially for most of length; abaxial scales absent. Ultimate segments elliptic to linear-oblong, not beadlike, the largest 4--10 mm, abaxially with reddish, scattered, sessile glands, adaxially glabrous; false indusia marginal to obscurely inframarginal, strongly differentiated, 0.25--0.50 mm wide. Sori ± continuous around segment margins. Sporangia containing 32 spores. n = 2 n = 90, apogamous.

Sporulating summer--fall. Rocky slopes and ledges, on quartzite or igneous substrates; 1900--2400 m; Ariz.; Mexico; Central America in Guatemala, Honduras.

The distinctive Cheilanthes arizonica is an apogamous triploid of unknown parentage. In the flora, it is known from about seven localities, all of which are situated within 50 km of the Mexican border.