Plants grayish green, or yellow above, brownish orange below, in beautiful shiny tufts. Stem cortex in 3–4 layers, hyaline cells with delicate fibrils, each cell with 1–3 large pores; central cylinder brownish. Stem leaves 1.0–1.2 mm × 1.0–1.1 mm, broadly lingulate with a broad apex; margins borders hyaline, differentiated, sometimes with fringed fibrils across the apex; hyaline cells mostly divided, often without fibrils, or with fibrils only in the upper cells. Branches in fascicles of 4–5, with 2–3 spreading. Branch leaves 2.5–3.5 mm × 2.0–2.5 mm, broadly ovate, strongly concave, narrowed at base, margins involute and hyaline, cucullate-concave and sometimes fringed and dorsally roughened at the apex; hyaline cells with large, rounded pores on the ventral surface, with numerous, half-circular pores at the opposite ends along commissural rows and membrane pleats in the upper cells on the dorsal surface; green cells in cross section rather large, nearly equilateral-triangular, exposed on the ventral surface. Dioicous. Sporophytes not seen.

Type. Puerto Rico.

Chinese specimens examined: NEI MONGOL: Da Xing An Ling (Greater Khingan Mt.), H.-F. Xie 71 (KUN, MO), H.-F. Xie 00046 (IFSBH, MO); Wufeng Shan (Mt.), H.-F. Xie 00027 (IFSBH, MO).

Habitat: submerged in bogs; Distribution: North Asia, North, Central, and South America.

This species is characterized by having stem leaves nearly as long as wide, branch leaves large and deeply concave, and by having both stem leaves and branch leaves with fringed fibrils at the apices.

Illustrations: C. Gao (ed.) 1994 (Pl. 15, figs. 10–12).