Commemorating Genthius, ancient King of Illyria, who is said to have discovered the medicinal properties of Gentian roots.

Shrubs or small trees, evergreen; latex white. Stems woody, without spines. Leaves opposite, stalked; blade well developed; colleters absent at base. Inflorescence axillary, cymose. Flowers scented, subsessile. Corolla salver-shaped; tube cylindrical; lobes convolute in bud, overlapping to the left. Corolline corona absent. Stamens enclosed, attached near top of tube, not sticking to style head. Disk absent. Fruit a globose to ellipsoid berry. Seeds 1 or 2, elliptic, flattened, not winged, without hair tufts.

All parts of the plant are poisonous. One species is commonly cultivated. Frost-sensitive.

Seeds.

Stems without spines, fruit a berry.

5 species in Africa and the Arabian peninsula.

Codd (1963), Kupicha (1982).

Source: Forster, P. (2002). Apocynaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.