Capsicum dimorphum

Capsicum dimorphum is a wild north-western South American species first published in 1849 as Brachistus dimorphus by John Miers and later transferred to Capsicum in 1891. The type material was collected in Colombia, and modern treatments place the species from Colombia through southern Ecuador to central Peru in wet montane forest, where it grows as a scrambling subshrub or shrub. Kew also records it as a medicinal plant.

The plant is an erect to scandent, profusely branched shrub or subshrub about 80 cm to 2 m tall, sometimes reaching 3 m, with a characteristic zig-zag branching pattern. Young stems are greenish-purple to maroon and usually densely hairy, while older stems become pale brown to golden-brown. One of the defining features of the species is its dimorphic paired leaves, with each node carrying a much larger major leaf and a much smaller minor leaf. The larger leaves are usually elliptic and about 4.5 to 12 cm long by 1 to 4 cm wide, while the smaller leaves are often rounder or ovate and much reduced in size. The foliage is green, and some leaves can show purple colouring beneath.

The flowers are borne singly or in small axillary groups of up to five on short, curved to pendent, non-geniculate pedicels about 5 to 14 mm long. The calyx is cup-shaped and usually toothless, though it can occasionally show 1 to 3 tiny mucro-like appendages, which is one of the main characters used to separate it from similar Andean species. The corolla is stellate, about 6 to 9.5 mm long and 8 to 12 mm across, and is entirely yellow or yellow with dark purple to maroon spotting inside and outside. This yellow corolla, short pedicels, and nearly toothless calyx are central to the identity of Capsicum dimorphum in modern treatments.

The fruit are small, globose to subglobose berries about 5 to 11 mm across. They begin bright or opaque light green and mature to reddish-orange or bright red. The berries are non-pungent, with a thick pericarp, and usually contain about 10 to 36 seeds. The seeds are brownish-black to black, and this dark seed colour is one of the notable features associated with the species and the Andean clade. Capsicum dimorphum is also variable in hairiness, leaf shape, and the presence or absence of purple spotting on the corolla, but its combination of dimorphic leaf pairs, yellow flowers, small red non-pungent fruit, and black seeds gives it a distinct identity among the wild Andean capsicums.