Astrolepis cochisensis

Stems compact; stem scales uniformly tan or somewhat darker near base, to 10 mm, margins ciliate-dentate to entire. Leaves 7–40 cm. Blade 1-pinnate to pinnate-pinnatifid, pinna pairs 20–50. Pinnae oblong, largest usually 4–7 mm, entire or asymmetrically lobed, lobes 1–4, broadly rounded, separated by shallow sinuses; abaxial scales completely concealing surface, ovate, usually 0.5–1 mm, ciliate with coarse marginal projections; adaxial scales sparse, deciduous, stellate to coarsely ciliate, mostly circular to elliptic, peltate, body more than 5 cells wide. Sporangia containing 32 or 64 spores.

Distribution

North America, Mexico.

Discussion

Subspecies 3 (3 in the flora).

Astrolepis cochisensis is reported to be toxic to sheep (F. P. Mathews 1945). Three cytotypes that occupy different ranges and/or habitats have been identified and are treated here as subspecies. These include a sexual diploid (subsp. chihuahuensis) found on calcareous substrates in the Chihuahuan Desert; an apogamous triploid (subsp. cochisensis), which inhabits primarily calcareous substrates in the Sonoran, Mojavean, and western Chihuahuan deserts; and an apogamous tetraploid (subsp. arizonica), which occupies primarily noncalcareous substrates in southern Arizona. Isozyme analyses suggest that subsp. cochisensis is an autotriploid derivative of the diploid subsp. chihuahuensis (D. M. Benham 1989). Both the isozymes and substrate preferences of subsp. arizonica indicate, however, that it is not a simple autotetraploid and that other taxa remain to be discovered within the Astrolepis cochisensis complex.

Selected References

None.

Lower Taxa

Astrolepis cochisensis subsp. arizonica, Astrolepis cochisensis subsp. chihuahuensis, Astrolepis cochisensis subsp. cochisensis

Key

1	Sporangia containing 64 spores; spores averaging 39– 46 µm diam.; plants of calcareous substrates in Texas, s New Mexico.	Astrolepis cochisensis subsp. chihuahuensis
1	Sporangia containing 32 spores; spores averaging 59– 86 µm diam.; plants of calcareous and noncalcareous substrates in California, Arizona, Nevada, w New Mexico, extreme w Texas, Oklahoma, Utah, n Mexico.	> 2
2	Spores averaging 59–70 µm diam.; plants primarily of calcareous substrates throughout Southwest.	Astrolepis cochisensis subsp. cochisensis
2	Spores averaging 72–86 µm diam.; plants primarily of noncalcareous substrates in s Arizona.	Astrolepis cochisensis subsp. arizonica