Hypopterygium tamarisci

Monoicous, dioicous or heteroicous. Asexual reproduction by filamentous gemmae borne on stems toward apices or caducous branches. Densely gregarious to isolated stems arising from rocks, tree ferns or tree trunks or less often logs or soil, up to 7 cm tall. Stems with an unbranched stipe section for up to 3.4 cm from base, erect from substrate, bending so that highly branched, frondose section is ±parallel with substrate or not bent and continuing in same direction as stipe, tomentose in stipe section at base or throughout; central strand present. Frond pinnately to tripinnately branched, palmate or umbellate. Leaves flat to concave abaxially, complanate throughout frond, usually isomorphic in stipe and base of rachis, otherwise dimorphic, in 3 ranks throughout frond, with a distinct or faint, sometimes interrupted border of more elongate cells 1–5 cells wide; laminal cells away from margins hexagonal, 15–60 μm long, 10–25 μm wide. Stipe and basal rachis leaves appressed to squarrose-recurved, symmetric or asymmetric, broadly ovate to triangular, ovate, elliptic or short-ligulate, 0.3–1.5 mm long, 0.2–1.5 mm wide; apex acute or acuminate; costa faint to distinct, extending (1/5–) 1/2–4/5 of leaf length; margin entire or weakly serrate, frequently partly or entirely recurved. Lateral frond leaves incubous, asymmetric, ovate, 0.7–2 mm long, 0.3–1.5 mm wide; apex acuminate; costa faint to distinct, extending 1/3–4/5 of leaf length; margin entire to coarsely serrate. Ventral frond leaves symmetric, orbicular to elliptic or ovate, 0.1–1.7 mm long, 0.1–2.5 mm wide; apex acuminate; costa faint to distinct, extending at least 1/4 of leaf length, often percurrent or excurrent; margin entire to coarsely serrate. Setae 6–25 mm long, light yellowish-brown to reddish-brown. Capsule globose to ellipsoid, horizontal to pendent, 0.5–2.3 mm long. Operculum short- to long-rostrate, 0.7–2.2 mm long.