Staurastrum cyrtocerum var. unguiculatum (Borge) G.J.P.Ramos & C.W.N.Moura, 2022

Ramos, Geraldo José Peixoto, 2022, Nomenclatural and taxonomic notes on Brazilian desmids IV, Notulae Algarum 224, pp. 1-7 : 5

Staurastrum cyrtocerum var. unguiculatum (Borge) G.J.P.Ramos & C.W.N.Moura , comb. nov.

Basionym: Staurastrum pseudosebaldi var. unguiculatum Borge, Arkiv for Botanik 19(17): 41, pl. 3: figs 19 a–d [“forma” fig. 20]. 1925.

Note: The variety unguiculatum was described by Borge (1925) based on samples collected in the São Luiz de Cáceres region, western Brazil. The main characteristic of this variety is the presence of convergent processes, which are much curved and like a helix in apical view. We consider, nevertheless, that the diagnostic features of this variety are more related to those of Staurastrum cyrtocerum Brébisson than Staurastrum manfeldtii Delponte , so a new combination is proposed here.

Förster (1969: 44) applied the name Actinotaenium peniomorphum var. latius (A.M.Scott & Prescott) Kurt Förster to material collected in the Amazon basin, Brazil. However, Actinotaenium peniomorphum is an illegitimate name as it is based upon Cosmarium peniomorphum A.M.Scott & Prescott, an illegitimate replacement name for Penium variolatum West & G.S.West ( West & West 1897: 77, pl. 368: fig. 23). Thus, Actinotaenium peniomorphum var. latius is also an illegitimate varietal name as it is included in an illegitimate species. Taxonomically, A. peniomorphum var. latius sensu Kurt Förster should is referable Actinotaenium crassiusculum (De Bary) Teiling.