Monographs Details: Riccia crystallina L.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Family:Ricciaceae
Scientific Name:Riccia crystallina L.
Synonyms:Riccia ochrospora Lindenb. ex Mont. & Nees, Riccia plana Taylor
Description:Species Description - Thallus in dense, spongy rosettes, 10-15 mm diam., with few, deep partitions, sometimes in gregarious patches; lobes approx. 2 mm long, to 14 mm wide, subdivided into short segments 2 mm wide, truncate, or rounded, or emarginate apically; dorsal side light blue-green and crystalline when moist, bluish green when dry. Median groove deep or absent. Pores small, larger toward central part of the rosettes. Ventral scales absent. Cross section of lobes 6 layers high; air chambers numerous in upper 3/4; ventral tissue thinner than dorsal, of large cells with pitted walls. Monoecious. Antheridial necks white, protruding. Archegonial necks pink, hardly protruding. Sporangia more numerous toward base of lobes, bulging ventrally. Spores yellow-brown, with darker ridges, ca. 400 per capsule, 60-87 µm diam.; wing complete, 4-6 µm wide, margin crenulate; distal face with 9-10(-11) complete areoles across diam., with rounded or bifid tubercles at comers of ridges; proximal face with complete areoles with similar tubercles, triradiate scar well marked, dark brown. Gametophytic chromosome number n = 8.

Discussion:Many authors have considered Riccia crystallina and R. cavernosa as conspecific (others used the name R. plana; e.g., Hässel de Menéndez, 1963). However, the different thallus color (bluish or glaucous in R. crystallina, yellow-green in R. cavernosa), spore color (yellow-brown in R. crystallina, red-brown to dark brown in C. cavernosa), and spore ornamentation (complete areoles in R. crystallina, incomplete ones in R. cavernosa) readily distinguish the 2 species.

Distribution and Ecology: Riccia crystallina has a wide range in Atlantic Europe, the Mediterranean area, Macaronesia, tropical and S Africa (Ethiopia, South Africa), Australia, and New Zealand. It has been recorded also from Arizona. In the Neotropics the species is rare and is known from Mexico (Mexico), Chile (O’Higgins (Gottsche et al. 1847), Valparaiso), Argentina (Rio Negro), and Uruguay. Many former records may belong to R. cavernosa, or to other species; those of the Bahamas (Evans, 1911), Peru (Montagne, 1845), Brazil (Bahía, Nees, 1833), Paraguay (Spruce, 1888) need confirmation. Riccia crystallina has been collected in the Neotropics on humid, weakly acidic or calcareous silt, mud, and sandy or clayey soil, from sea level to 3300 m.

Distribution:México Mexico North America| Rio Negro Argentina South America| Valparaíso Chile South America| Colonia Uruguay South America| Montevideo Uruguay South America|