Riccardia Gray

Reeb, Catherine & Gradstein, Robbert, 2020, A taxonomic revision of Aneuraceae (Marchantiophyta) from eastern Africa with an interactive identification key, Cryptogamie, Bryologie 20 (2), pp. 11-34 : 16

Genus Riccardia Gray

REMARKS

About 100 species worldwide (Söderström et al. 2016). Based on the results of species delimitation analysis ( Reeb et al. 2018), 12 species are recognized in Africa. Eleven of these occur in eastern Africa ( Fig. 1 ) and three are new to science: R. gasparii sp. nov., R. martinii sp. nov. and R. vohimanensis sp. nov. In addition, Riccardia multifida , a species known from South Africa, may be expected to occur in eastern Africa and is therefore included in this treatment. The genus Riccardia is characterized by the 1-3-pinnately or palmately branched thalli with a narrow, 0.3-1.5(-2) mm wide axis and short sexual branches. The archegonia and antheridia are developed in two straight rows on separate branches. The genus is closely related to Aneura and Afroriccardia but the latter two genera have broader, less branched axes (more than 2 mm wide). In early literature, Riccardia was part of Aneura (e.g. Stephani 1898-1924).

Figures

FIG. 1. — RaxML tree of Aneuraceae of eastern Africa based on concatenation of chloroplast matK, psbA-trnH and trnL-F sequences (modified after Reeb et al. 2018). Numbers in brackets are number of specimens analysed, numbers on branches are bootstrap values, obtained by fast bootstrapping.