Monographs Details: Riccia sorocarpa Bisch.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Scientific Name:Riccia sorocarpa Bisch.
Synonyms:Riccia antarctica Steph., Riccia chilensis Steph., Riccia rauhii Buchloh
Description:Species Description - Thalli in rosettes 2 cm in diam.; lobes 3-10 mm long, 0.5-2 mm wide, rounded apically, 2-3 times forked, the basal dichotomy deep, of 2/3-3/4 of lobe length; dorsal side pale green, rarely bluish green, with narrow, hyaline margins; flanks, parts of dorsal side and margins sometimes tinged with violet. Median groove deep at lobe apex, becoming shallower below but reaching lobe base. Epidermis of rounded or pyriform cells, disintegrating except in groove, basal walls and walls of the hypodermal cells strongly thickened. Ventral scales pale, not reaching lobe margins. Cross section of lobes slightly wider than high near apex, 2-3 times as wide as high below; dorsal edge obtuse and ascending laterally; flanks obliquely ascending, with independent row of long and narrow cells ending in a long, rounded cell apically. Monoecious. Antheridial necks hardly protruding, pale. Sporangia large, black, bulging on ventral side. Spores tetrahedral, 70-98 µm diam., dark red with black-red ornamentation; wing 5-7 µm wide, wider near the pores, irregular, granulose and crenulate on margin; distal face with 8-10(-14) areoles across diam., with rather thin ridges and large tubercles, the 4 areoles near pole often larger; proximal face covered with granules, or vermiculate, or with short, sinuose ridges, ridges of triradiate scar slender. Gametophytic chromosome number n = 8.

Discussion:Riccia sorocarpa has a smooth thallus surface with a very narrow, hyaline margin, and epidermal and hypodermal cells with thickened walls. These characteristics distinguish the species from all other neotropical Riccia species. Riccia sorocarpa has a wide geographical range and is able to cope with a variety of habitats, from tropical areas to arctic zones. Its morphological characteristics are stable, with the exception of pigmentation of the flanks, degree of thickenings of the cell walls of the epidermal and hypodermal cells, spore diam., and width of the spore wing. Geographical correlation of morphological variation has not been observed.

Schuster (1992a) described the xeromorphic subsp, erythrophora Schust. (J. Hattori Bot. Lab. 71: 274. 1992. Type. U.S.A. California: San Diego C°, 1.5 km W of Potrero, Schuster 82-146) from the SW U.S.A. and Mexico (Baja California: 20 km S of Te-cate, Schuster 82-153). It differs from subsp, sorocarpa by the only 1-2 times forked lobes, the less conspicuously thickened walls of the epidermal and hypodermal cells, and the vinaceous or purplish scales. These characteristics hardly deserve taxonomic status.

Distribution and Ecology: Riccia sorocarpa is widely distributed in Europe to 70° N, in the Mediterranean area, Macaronesia, the Sahara, S Africa, Asia (SW Asia, Siberia, China), Australia, New Zealand, and Hawaii. It is known from NW Greenland, from most of the states of the U.S.A., but seems to be infrequent in the Neotropics. It has been recorded from Mexico (Baja California (Schuster, 1992b), D. F., Guadalupe Is. (Howe, 1934), Mexico, Oaxaca), Costa Rica, Peru (Ancash, Cuzco, Junín, La Libertad), Brazil (Pernambuco (Yano & Andrade Lima, 1987)), Chile (Valparaiso), Argentina (Catamarca (Hässel de Menéndez, 1958), Mendoza (Hassel de Menéndez, 1958), Neuquen (Hässel de Menéndez, 1963), Rio Negro (Hässel de Menéndez, 1963)), and Uruguay. The species has been collected in humid to semi-arid climatic areas, on various types of soils (acidic or basic, sandy, clayey or silty), over acidic or calcareous rocks, usually in exposed situations, also on river borders and in gardens, from sea level to 4530 m.

Distribution:Distrito Federal Mexico North America| México Mexico North America| Oaxaca Mexico North America| Valparaíso Chile South America| Cartago Costa Rica Central America| Ancash Peru South America| Cusco Peru South America| La Libertad Peru South America| Tacuarembó Uruguay South America|