The taxonomic affinity of Carum piovanii Chiov. and some Bunium species (Apiaceae)

• A new nomenclatural combination Afroligusticum piovanii is proposed.
• Bunium nothum is placed in a new section, Austrobunium.
• Bunium kandaharicum is treated as a synonym of Elwendia stewartiana.

The systematic position of three Apiaceae taxa, Carum piovanii, Bunium nothum and Bunium kandaharicum, is clarified based on morphological and nrITS sequence data. The phylogenetic analyses place C. piovanii within the African peucedanoid genus, Afroligusticum and not with its congeners. Although C. piovanii differs considerably from Afroligusticum in underground organs (spindle-shaped or subcylindrical tubers vs. rhizomatous woody rootstocks), size of leaflets (up to 4 mm long vs. over 8 mm long), and petal color (white vs. mostly greenish or yellow), it is similar carpologically (obtuse-keeled dorsal ribs and narrowly-winged marginal ribs). As a result the new combination Afroligusticum piovanii is proposed. A new section, Austrobunium, is described to accommodate the South Indian B. nothum based on the well-developed calyx teeth not found in the rest of the genus. The Afghanian species, B. kandaharicum, is reduced into synonym with Elwendia stewartiana.