Monographs Details: Riccia dussiana Steph.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Scientific Name:Riccia dussiana Steph.
Description:Species Description - Thalli spongy, with gregarious lobes; lobes 5-7 mm long, 1.5-2 mm wide, rounded and slightly emarginate apically, 3-4 times forked, the basal dichotomies deep, the apical short; dorsal side pale yellowish when dry, or pale green with pale yellow, narrow, wavy and translucent margins. Median groove deep apically, vanishing below. Pores 55-85 µm diam., bounded by 2 rings of 4 cells. Ventral scales short, not reaching lobe margins, hyaline, or violet, or spotted with violet. Cross section of lobes 0.4-0.5 mm high, 2-4 times as wide as high; dorsal edge with narrow, thin lateral wings ending in a single cell, often reflexed toward ventral side; flanks ± concave, violaceous, or hyaline, or spotted with violet; ventral edge convex; dorsal tissue spongy, 1/3-1/2 of lobe height, cells with longitudinal, pitted strips; air chambers in l(-2) layers; ventral tissue with thin-walled, pitted cells. Monoecious. Antheridial necks white, protruding. Archegonial necks colorless, hardly protruding. Sporangia bulging ventrally. Spores light brown, 72-86 Jim diam.; wing yellow-brown, 5-7 Jim wide, margin thickened and granulose; distal face with 8-11 areoles across diam., with dark red-brown, thick ridges and weak tubercles; proximal face with areoles smaller than those of distal face, often incomplete, with irregularly thickened ridges, triradiate scar weak.

Discussion:Riccia dussiana is distinguished from other species of sect. Ricciella by its yellowish thalli and its thin, wavy lobe margins.
Distribution:Martinique South America| Loreto Peru South America| Saint-Laurent-du-Maroni French Guiana South America| French Guiana South America|