Monographs Details: Riccia elliottii Steph.
Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press
Description:Species Description - Thalli in irregular, gregarious mats; lobes 2-3 times forked, 8 mm long, 1.5-2 mm wide, thin, rounded, and slightly emarginate apically; dorsal side light brown or greenish brown when dry, light green when moist, with narrow, hyaline, slightly undulate margins; ventral side brown, violaceous-brown or reddish. Median groove deep apically, vanishing rapidly below. Epidermal cells disintegrating except in groove, rounded. Ventral scales not seen. Cross section of lobes 2-6 times as wide as high; dorsal edge acute laterally with hyaline wings; flanks obliquely ascending; ventral edge convex; dorsal tissue in 3-4 layers. Monoecious. Spores tetrahedral, 80-90 µm diam., red-brown; wing 4 µm wide, light brown, granulose; distal face with 4-5(-6) areoles across diam., granulose inside, with high, red-brown or nearly black ridges and large tubercles; proximal face with 3-6 areoles per facet, larger than those of distal face, with high, narrow ridges at pole, with lower ridges and weak tubercles, progressively vanishing toward equator, triradiate scar weak.
Discussion:Riccia elliottii is allied to R. breutelii and R. brittonii. However, it differs from these two species by its thallus characteristics (see description) and by the spore wall ornamentation, with a smaller number of areoles across the distal and proximal faces.
Distribution:Dominica South America