Plants floating to submerged, in streamers to 80 cm long, dark green to yellow green, tightly attached to substratum at extreme base and only sparsely branched above. Leaves erect to erect spreading, mostly rather distantly arranged but occasionally approximate to slightly imbricated especially on branches, strongly 3-ranked throughout. Leaves on main axis to 8 mm long, ovate with a moderately well defined acumen, 2–5: 1, tightly conduplicate keeled with the keel uniformly curved in lateral view. Branch leaves to 4 mm long, narrowly lanceolate with a long acuminate apex, 4–6: 1, deeply concave to somewhat keeled. Margins plane throughout or subtubular inrolled at the apex of the branch leaves, entire throughout or with a few serrulations near apex, not decurrent. Median cells smooth. long rhomboidal to linear, with straight and thin lateral walls, 10–15 µm broad, 6–8: 1. Alar region not auriculate, with its cells usually in a rather poorly demarcated patch, quadrate to short rectangular, somewhat inflated but with some wall thickening. Apical cell of stem leaves markedly shorter than adjacent cells, often nearly isodiametric. Costa absent but with the extreme leaf base with an irregular central patch of multistratose lamina. Pseudoparaphyllia orbicular, tightly overarching the bud. Axillary hairs to 100 µm, 5–6 celled with two basal brown cells.
Dioicous with male plants typically somewhat smaller than the females. Perichaetial leaves very broadly oval to suborbicular, to 2.5 mm long, strongly convolute around the capsule, truncate to rounded, often lacerate at apex. Seta to 0.5 mm long, erect, hidden among the perichaetial leaves. Capsule brown, symmetric and erect, not distorted or sulcate. Urn oblong, to 2.5 mm, about 2: 1. Exothecial cells to 30 µm wide, 1–5: 1, not in regular rows. Operculum conic, about 1/4 as long as urn. Exostome teeth spirally incurled when dry or erect and united at their apices, narrowly lanceolate, about 10: 1, strongly papillose, often united at their apices. Endostome without a basal membrane, as long as the exostome with the segments linear, not keeled, appendiculate along the transverse bars so that the entire endostome resembles a trellis. Spores smooth to very lightly papillose, 15–18 µm.
Ecumbent to ascending. Leaves to 1.0 mm, 2–4:1, complanate; not plicate, oblong-ovate, sometimes contracted at the middle into a ligulate distal portion, rounded to obtuse at apex, imbricate when dry and little changed when moist; laterally inserted leaves asymmetric with their postical margins broadly incurved at base,. Margins plane, at base somewhat cordate but not decurrent, serrulate to serrate above the middle, sometimes serrulate throughout. Median cells smooth, 6–9 µm wide, 2–5:1, thick-walled with lumen/wall ratio to 1:1, but not pitted. Alar cells quadrate to transversely elongate in a small group up to 10 cells in each dimension, thick-walled, grading into laminal cells. Apical cells rhomboidal, dearly isodiametric. Costa extending about 1/2 to 3/4, often forked distally. Pseudoparaphyllia deltoid to orbicular, strongly overarching the bud. Axillary hairs 2–3 celled, to 100 µm with one basal brown cell, not offset from leaf insertion. Rhizoids red-brown, 6–8 µm, smooth, inserted on stem immediately below abaxial costal insertion.
Dioicous with male plants smaller than females. Perigonia on main axis or terminal on short lateral branches. Perichaetia on main axis, to 3 mm long in an acicular cluster, strongly convolute around the seta. Perichaetial bracts ecostate or with a narrow costa present only near leaf middle, abruptly acuminate from a ligulate-lanceolate base, cells long rectangular, to 25:1. Seta 5–10 mm long, short-exserted. Capsule brown, curved and inclined, not distorted or sulcate when dry, somewhat strangulate at mouth. Urn to 1.8 mm, about 2–3:1. Exothecial cells 1–3:1, 12–18 µm wide, thick-walled with a lumen/wall ratio about 3:1, stomata restricted to neck. Operculum short-rostrate, about 1/2 as long as urn. Exostome horizontally striate below, becoming low papillose above, red-brown. Endostome segments lightly papillose, open on keel, narrow, about as long as exostome with basal membrane about 1/4 of total length. Cilia 2,well-developed. Spores low papillose, 12–15 µm.