Studies in the genus Riccia (Marchantiales) from southern Africa. 19. Two new species: R. pulveracea., section Pilifer and R. bicolorata, section Riccia, group ‘Squamatae’

Abstract

R. pulveracea, specimens of which were collected by Duthie and tentatively referred to R concava by her. is described here, following the recent collection of fresh material. This species is distinguished from other members of section  Pilifer (Volk 1983) by low. generally two-celled, free-standing dorsal cell pillars, which when dry, appear powdery, hence the specific epithet.

R bicolorata. section Riccia. group 'Squamatae' occurs in the Cape but is rarely collected, and is characterized by bicoloured scales, of which the wide hyaline margins are heavily encrusted with calcium deposits. It is somewhat similar to R. pottsiana, but larger, and its scales are not so regularly arranged.