Monographs Details: Riccia albida Sull.
Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press
Description:Species Description - Thalli in partial rosettes, or in gregarious patches; lobes 2-3 times forked, 3-5 mm long, 0.8-1.8 mm wide, rounded apically or shallowly emarginate; dorsal side white, roughened by projecting epidermal cells covered with chalk, light green in groove, margins rounded, not inflexed when dry. Median groove deep, persistent to the lobe base. Epidermal cells bulging, thickened, conical or pyriform. Pores rounded, 30 mm diam., or elongate, 25-35 × 50-60 µm. Ventral scales rare, small, or absent. Cross section of lobes 0.3-0.7 mm high, 1.5-2.5 times as wide as high; dorsal edge rounded laterally, flanks rounded, ventral edge flat or slightly convex; dorsal tissue in 2-\ layers, hyaline, sometimes with pink strip basally; ventral tissue chlorophyllose, of smaller cells. Dioecious. Sporangia not bulging. Spores sub-spherical, 65-85 |im diam., yellow-brown or red-brown, wingless, nearly smooth or weakly plicate and rugulose on both faces, triradiate scar indistinct.
Discussion:Riccia albida is allied to the Mediterranean and Central Asiatic R. crustata Trab. The two species can be distinguished by their epidermal cells; those of R. albida are more distinctly bulging, and are separated by pores of different shape and size.
Nuevo León Mexico North America