Hypopterygium didictyon

Dioicous. Asexual propagules absent. Densely gregarious to isolated stems arising from soil, rocks, logs or tree trunks, up to 4 cm tall. Stems with an unbranched stipe section for up to 4 cm from base, erect from substrate, bending so that highly branched, frondose section is ±parallel with substrate, often tomentose throughout stipe, glabrous when young or occasionally remaining glabrous; central strand present. Leaves flat, complanate on branches and at least apical half of rachis, isomorphic in stipe and base of rachis, otherwise dimorphic, in 8 ranks along stipe and base of rachis, otherwise in 3 ranks, with a distinct border of more elongate cells 1–5 cells wide; laminal cells short-linear, rectangular or hexagonal, 20–95 μm long, 5–30 μm wide. Stipe and basal rachis leaves appressed to wide-spreading, symmetric, deltoid to broadly ovate, 0.4–1 (–1.5) mm long, 0.2–1.5 mm wide; apex acute or acuminate; costa absent to distinct and extending c. 4/5 of leaf length; margin entire. Lateral frond leaves incubous, asymmetric, ovate to oblong, 0.5–2 mm long, 0.2–1.5 mm wide; apex apiculate; costa distinct, extending 2/3–4/5 of leaf length; margin weakly to coarsely serrate. Ventral frond leaves symmetric, orbicular, ovate to oblong, 0.2–1.5 mm long, 0.2–1 (–1.5) mm wide; apex apiculate; costa distinct extending at least ½ of leaf length, usually percurrent or excurrent; margin weakly to coarsely serrate. Setae 7–18 mm long, light yellowish-brown to reddish-brown. Capsule ellipsoid, horizontal to pendent, 0.8–2.4 mm long. Operculum long-rostrate, 2–2.5 mm long.