A revision of the genus Marlothiella (Apiaceae)

Marlothiella gummifera is a small perennial shrublet endemic to the Skeleton Coast of Namibia. Surprisingly it was found that the general fruit morphology agrees with that typically found in Saniculoideae and other basally diverging taxa. It is remarkable in the combination of a compound umbellate inflorescence, slightly heteromorphic fruits and dispersed crystals (typical of basally divergent genera of the subfamily Apioideae) with several characters typical of the subfamily Saniculoideae: large rib ducts, no vittae, unicellular stellate trichomes (not yet observed in any other genus of the family), and ventral vascular bundles that are poorly developed or absent. New insights into the morphology and possible systematic affinities of this poorly known monotypic genus are presented, together with a detailed taxonomic revision.