Riccia violacea M.Howe

• Authority

  Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)

• Family

  Ricciaceae

• Scientific Name

  Riccia violacea M.Howe

• Type

  Type. Puerto Rico. Mona Is.: between Sardinero and Ubero, Britton et al. 1749b (holotype, NY).

• Synonyms

  Riccia violacea var. violacea, Riccia violacea var. laevis Jovet-Ast

• Description

  
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  Species Description - Thalli in gregarious patches; lobes 1.5-5 mm long, 0.7-1 mm wide, 1-3 times forked, obtuse or slightly emarginate apically, margins obtuse; dorsal side blue-green, with dark violet margins when moist; flanks inflexed when dry, dark red-violet, with wide, purplish strip inside; ventral edge colorless. Median groove shallow apically, wider and flattened below. Epidermis disintegrating except in groove, cells rounded, mamilliform. Ventral scales short, irregular in shape, 2-3 cell layers in height, bordered by hyaline or violet projecting cells, or by hyaline, papilliform cells. Papillae numerous, on lobe margins and on upper part of flanks, hyaline, sometimes violaceous, smooth or granulose, rounded or obtuse apically, 25-130 µm long, 25-45 µm wide basally, erect or slightly arched, together with nearly acute, hyaline, strongly granulose papillae. Cross section of lobes 12 times as wide as high, without wings; dorsal side rounded laterally; flanks ascending, rounded apically; ventral edge convex or nearly flat. Dioecious. Antheridial necks protruding, violet. Spores subspherical, 85-115 µm diam., black or dark brown, wingless, crenulate on margin; distal face with 12-17 areoles across diam., with thick, black ridges and large tubercles; proximal face with similar ornamentation but usually without tubercles, triradiate scar weak.

• Discussion

  Riccia violacea is related to R. atromarginata var. atromarginata, but in R. violacea the papillae are shorter, absent on the dorsal side of lobes. The species has been included by Schuster (1992b) as a synonym of R. atromarginata subsp, atromarginata. This synonymy is not accepted here (see under R. atromarginata).

• Distribution

  Puerto Rico South America|