Monographs Details: Riccia paraguayensis Spruce
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Synonyms:Ricciella macropora Steph.
Description:Species Description - Female thalli in rosettes of 2-4 cm diam., male thalli smaller, 1 cm diam.; lobes 10-15 mm long, 2-3 mm wide, thin, translucent, obtuse and slightly emarginate apically ; 3-4 times forked, the basal dichotomy deep and diverging; dorsal side bright green and shiny when dry. Median groove distinct apically, evanescent below. Pores rounded or ovate. Ventral scales absent. Cross section of lobes very thin, of few layers, often restricted on the lateral sides to dorsal and ventral epidermis and 1 layer of air chambers. Dioecious. Antheridial necks white, protruding. Sporangia bulging ventrally. Spores brown, 60-70(-80) µm diam.; wing thin, yellowish, 2-3 µm wide, granulose; distal face with 9-10(-13?) areoles across diam., with thin ridges and small tubercles; proximal face with 30-40 areoles per facet, rarely with a central tubercle, smaller than those of distal face, triradiate scar thin.

Discussion:The shiny lobes of Riccia paraguayensis recall R. membranacea, but the 2 species have completely different spore ornamentation patterns. Hassel de Menéndez (1963) treated R. subsimilis as a synonym of R. paraguayensis. Riccia subsimilis has spores remaining in tetrads, however, and is considered a synonym of R. curtisii in the present treatment.
Distribution:Mato Grosso do Sul Brazil South America| Rio Grande do Sul Brazil South America| Paraguay South America| Corrientes Argentina South America| Colonia Uruguay South America|