Fissidens ovatus Brid.

Plants large, in loose groups, light green; terricolous, frequently semi-aquatic. Stems 5-10 mm long, occasionally branched; in section elliptical, central strand present, inner cortical cells large, in 3(4) rows, outer cortical cells stereids, in 3 rows, reddish; axillary hyaline nodules numerous, of 6-10 enlarged, clear or chlorophyllous cells, enclosed by vaginant laminae. Leaves equally spaced, erect with circinate tips dry, erect-spreading wet, occasionally somewhat undulate; oblong to oblong-lanceolate, 2.0-3.2 mm long; apex obtuse to broadly acute, cuspidate; margins elimbate, entire to serrulate, frequently serrate at apex; costa strong, short-excurrent, flex-uous above. Vaginant laminae ? of leaf length, termination of one blade submarginal or laminal; dorsal lamina not narrowing toward stem, rounded proximally, generally crumpled against stem. Upper laminal cells rounded-hexagonal, 8-12 µm long, incrassate, mammillose; quadrate marginally, smooth; cells of vaginant laminae quadrate to rectangular, smooth, becoming smaller toward margin. Dioicous. Perigonia axillary, gemmate. Perichaetia terminal or infrequently axillary; leaves not differentiated. Seta to 10 mm long, reddish yellow; capsule horizontal, urn curved, 1.2-1.5 mm long, red-yellow; exothecial cells rectangular, incrassate; peristome teeth deeply cleft, red-yellow; operculum conic-rostrate, 0.6 mm high; spores round, 15-20 µm, smooth.