Selaginella peruviana
Selaginella peruviana (Milde) Hieron.
(of Peru, the species ranging to South America)
Local names: Peruvian spike-moss
Plant forming loose mats; stems prostrate, with upper and lower surfaces different in appearance (leaves upswept or curving upward making the views of the leaf-covered stems from above and below distinctly different); rhizophores scattered along entire length of stem; leaves tightly appressed to ascending, apically with an elongate rounded bristle 0.3–0.8 mm long, all of one kind though leaves on underside of stems widest at base (linear to linear-lanceolate in outline) or at least definitely not narrowed at base, usually pubescent (sometimes glabrous), decurrent at base, marginally ciliate, those on upper side slightly smaller, abruptly adnate at base; strobili solitary, quadrangular, 5–20 mm long; sporophylls ovate-deltate to ovate, with distinct apical bristle. Usually on rock, slopes, crevices, ledges, on sandstone or igneous substrates, less commonly on soils (sandy or clay); primarily Trans-Pecos (e.g., Brewster Co., Warnock 9171, BRIT, TEX-LL; El Paso Co., Correll & Johnston 24390-B, BRIT, TEX-LL) and e Edwards Plateau (e.g., Burnet Co., G.L. Webster 1982, TEX-LL) with a slightly disjunct report from Comanche Co. (Stanford 1971) in the Cross Timbers & Prairies; NM, OK, TX; also Mexico and South America. Sporulating Jun–Oct. [Bryodesma peruviana (Milde) Sojak; S rupestris (L.) Spring forma peruviana Milde; S. sheldonii Maxon] Peruvian spike-moss has an interesting biogeography— it occurs in the sw U.S. and Mexico and is distantly disjunct to Argentina, Bolivia, and Peru (Tryon 1969; Mickel & Smith 2004). Yarborough and Powell (2002) noted that this species “occasionally occurs intertwined in the same mixed mats with S. rupincola in the Caballos Novaculite area S of Marathon and with S. underwoodii or S. mutica in the Davis Mountains.” It is similar to S. arizonica, but can be distinguished by the characters given in the key to species.