Isopterygium homomallifolium Redfearn, Bryologist 76: 440, figs. 1-11. 1973

Plants in thin to dense mats, yellowish. Stems 1.5 cm, 1-2 mm wide, occasionally complanate-foliate. Leaves erect-spreading, upturned-homomallous, distant to close and overlapping, lanceolate to ovate-lanceolate, symmetric, smooth, 0.8-1.2 × 0.3-0.5 mm; margins plane, serrulate nearly to base; apex long-acuminate; ecostate or costa double, weak; alar cells poorly differentiated, few short-rectangular cells often present; medial laminal cells 60-120 × 5-9µm; distal cells smooth. Specialized asexual reproduction absent. Sexual condition autoicous. Seta 0.8-1.6 cm. Capsule erect, horizontal, or slightly cernuous, ellipsoid, 1.4-1.7 mm; operculum long-conic to short-rostrate. Spores 9-16 µm.

Capsules mature spring-summer. Rock, under rock ledges; moderate to high elevations (1400-2000 m); Ariz., N.Mex., Tex.; Mexico (Sonora).

Pseudotaxiphyllum homomallifolium occurs in Cochise, Navajo, and Santa Cruz counties in Arizona, Doña Ana County, New Mexico, and Kimble County, Texas.

Pseudotaxiphyllum homomallifolium is distinguished from the other two species of the genus in the flora area by its long-acuminate, upturned-homomallous leaves with broad laminal cells. The plants somewhat resemble Campylium, but the leaf apices are not channeled like the leaves of that genus. Foliose pseudoparaphyllia were attributed to P. homomallifolium when Redfearn described the species, but these are probably not pseudoparaphyllia. The multicellular structures rarely found on the stems appear to be part of a developing branch primordium because they sometimes are not even evident, and they are not located on the stems at the bases of mature branches as are typical pseudoparaphyllia.