Clarification of Massonia echinata and some other frequently misunderstood Massonia species (Asparagaceae, Scilloideae), with the description of M. pseudoechinata and M. roggeveldensis - Martinez-Azorin, M; Pinter, M; Crespo, M B; Slade, J; Deutsch, G; Wetschnig, W (Phytotaxa, 2015)