Iochroma Benth. (1835), in the family Solanaceae, contains around 20 species in cool parts of tropical South America.
Description Shrubs to 4m, often with weeping flowering branches. The leaves are alternate, deciduous or evergreen, simple, and often velvety-hairy. The flowers are purple or reddish, long-tubed, hanging in clusters. Sepals 5, joined at the base to form a bell-shaped calyx. Petals 5, joined for most of their length into a tube. Stamens 5, in the mouth or slightly exserted from the flower. Ovary superior, 2-celled, with numerous ovules per cell; style 1, simple, slender. Pollination is by hummingbirds and insects, especially bumblebees. The fruits are fleshy berries, usually orange when ripe.
Key Recognition Features The tubular, purple or red flowers around 5cm long with a bell-shaped calyx.
Evolution and Relationships The 3 genera Iochroma, Dunalia Kunth, and Acnistus Schott are very similar, differing mainly in that Dunalia has shorter stamens with small cusps on the sides of the filaments. Acnistus is now restricted to 1 species, A. arborescens (L.) Schldl. from South America. The species shown here, I. australe Griseb., has been placed in all 3 genera at different times.
Ecology and Geography In rocky places and scrub in the lower parts of the Andes from Mexico to Argentina.
Comment Iochroma australe is an attractive and hardy shrub or small tree, which has become naturalised in a few places outside its native Argentina. The other species are more tender, but are widely grown in Mediterranean gardens and in areas of North America where there is little or no frost.
Iochroma australis Griseb., syn. Dunalia australis (Griseb.) Sleumer, Acnistus australis (Griseb.) Griseb. (Solanaceae) An evergreen or semi-evergreen shrub with pendent violet-purple flowers, native of N Argentina, growing in montane forest to about 3000m, flowering in late spring and early summer. Spreading shrub to 3m or more, developing long leafy branches. Leaves 5–10cm, elliptic or oblong, rather leathery. Flowers 3–6cm long, narrowly trumpet-shaped with 5 shallow triangular lobes, borne in small clusters in the upper leaf axils. Min. -5°C or lower in a sheltered site. A most elegant shrub when the arching branches are hung with flowers. Iochroma cyaneum (Lindl.) Green, differs mainly in the shorter stamens, each with a pair of lateral cusps from the filament.