Monographs Details: Riccia paranaensis Hässel
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Description:Species Description - Thalli in complete or partial rosettes, 0.7-3 cm diam., often with crowded lobes in 2-3 layers; lobes 1-3 mm long, 0.5-1.2 mm wide, deeply 3-4 times forked, rounded or emarginate apically; dorsal side light green or yellowish green when dry, basally violet, or tinged with violet or pink only on margins and ventral side. Median groove deep, distinct apically on terminal segments only. Pores bounded by 3-4 cells. Ventral scales absent, or apically present, colorless. Cross section of lobes 2-2.5 times (toward base of lobes 3-4 times) as wide as high; dorsal edge rounded laterally; flanks oblique; ventral edge hardly convex; air chambers in 1-3 layers; ventral tissue in 3-5 layers. Monoecious. Archegonial necks protruding, 25 µm long, violet. Sporangia bulging ventrally. Spores light brown with darker ornamentation, or red-brown, 62-76(-84) µm diam.; wing irregular and narrow, and weakly undulate, sometimes discontinuous in part, ± granulose, 2-2.5 µm wide; distal face with 5-8 areoles across diam., with thin ridges and triangular tubercles; proximal face with about 20 areoles with thin ridges per facet, smaller than those of distal face, triradiate scar weak.

Discussion:Riccia paranaensis is related to R. stenophylla, with which it shares narrow lobes. However, the thalli of R. paranaensis are crowded and arranged in several layers in the patches, and the spore wall of the distal face lacks ridges or tubercles inside the areoles but instead has tubercles on the ridges. Riccia paranaensis may also be compared to R. huebeneriana Lindenb. In the latter species the lobe dichotomies are distinctly shorter, the dorsal side of the lobes is bright green, often tinged with purple or violet near apex and above sporangia, and the scales are often violet. In R. paranaensis, the scales are hyaline and the spores are smaller.
Distribution:São Paulo Brazil South America| Mato Grosso Brazil South America| Rio Grande do Sul Brazil South America| Espirito Santo Brazil South America| Buenos Aires Argentina South America|