Monographs Details: Riccia stenophylla Spruce
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Family:Ricciaceae
Synonyms:Riccia oerstediana Lindenb. & Hampe, Riccia hosseusii Herzog
Description:Species Description - Thallus in crowded mats or forming partial rosettes; lobes 3-5(-20) mm long, 0.3-0.5 mm wide, slightly wider at level of sporangia, 2-5 times forked, obtuse or slightly emarginate apically; dorsal side light green. Median groove distinct apically, vanishing below. Pores bounded by 4(-6) cells, irregular in size. Ventral scales semi-lunate, sometimes the apical conspicuous, extending beyond lobe apex. Cross section of lobes 2-3 times as wide as high; dorsal edge rounded or obtuse laterally; flanks oblique; ventral edge convex; air chambers in 2-3 layers; ventral tissue in 2-4 layers. Monoecious. Sporangia large, 0.5 mm diam., bulging ventrally. Spores brown or light red-brown, 65-74 |im diam.; wing lighter, complete, 5-7 Jim wide, tuberculate-papillose; distal face with 4-5 ± complete areoles across diam., each with a tubercle or a simple or branched ridge in the center proximal face with areoles smaller than those of distal face near equator, delimited by low ridges, becoming incomplete toward pole and replaced by ± sinuose and branched ridges, triradiate scar well marked. Gametophytic chromosome number n = 8.

Discussion:Riccia stenophylla resembles R. fluitans and R. limicola. However, the spores of the latter species have 5-7 areoles with granulose ridges across the distal face, and the areoles of the proximal face are complete. Riccia fluitans has granulose spores with 5-7 areoles across the diam, of the distal face, without tubercles or ridges in the center, whereas in R. stenophylla the spores are not granulose and have 4-5 areoles across the diam, of the distal face, with tubercles or ridges in the center. The spores of Riccia canaliculata Hoffm., a species known from Europe, the Mediterranean, and N America, are larger (80-97 µm).

Distribution and Ecology: Riccia stenophylla is known from the U.S.A. (Florida, North Carolina, Texas) and the Neotropics: Mexico (Aguascalientes, Jalisco), Guatemala, Costa Rica, Panama, Peru (Cajamarca, Piura), Brazil (Bahfa, Espiritu Santo, Goias, Mato Grosso, Parana, Pernambuco, Rio de Janeiro, Rio Grande do Sul, Santa Catarina, Sao Paulo), Paraguay, Argentina (Buenos Aires (Hassel de Menendez, 1963), Cordoba (Hassel de Menendez, 1963), Formosa), and Uruguay. The species seems to be quite common and grows on sandy or clayey, sometimes granitic soil, or on rocks, exposed or sheltered, in gardens, plantations, and along forest borders, from low elevations to 2000 m.

Distribution:São Paulo Brazil South America| Goiás Brazil South America| Mato Grosso Brazil South America| Bahia Brazil South America| Rio de Janeiro Brazil South America| Santa Catarina Brazil South America| Pernambuco Brazil South America| Rio Grande do Sul Brazil South America| Espirito Santo Brazil South America| Paraná Brazil South America| Guatemala Central America| Veracruz Mexico North America| Jalisco Mexico North America| Aguascalientes Mexico North America| Formosa Argentina South America| Coclé Panamá Central America| Alajuela Costa Rica Central America| Cartago Costa Rica Central America| San José Costa Rica Central America| Boquerón Paraguay South America| Presidente Hayes Paraguay South America| Cajamarca Peru South America| Piura Peru South America| San José Uruguay South America| Mexico North America| Costa Rica South America|