Alstonia congensis var. glabrata Engl.

Alstonia congensis is a tall forest tree reaching 30 m high; bole cylindrical, fluted at the base or columnar up to 7m. Bark rough with large solitary lenticels. Slash yellow-brown, thin abundant white latex. Leaves simple, in whorls, obovate or spathulate, up to 12 cm long; apex rounded, often apiculate or sometimes emarginate; venation conspicuous. Inflorescence glabrous and capitate. Fruit a black dehiscent follicle, long and narrow, up to 40 cm long. Seeds numerous, hairy. Alstonia congensis is considered endangered in its native range. The specific epithet refers to Congo, Africa where specimens for scientific identification of the species were first collected.

A. congensis is a hermaphroditic tree with wind dispersed seeds.

A. congensis is an evergreen rainforest tree occuring in S. Nigeria and extending to Democratic Republic of Congo and Angola. A. congensis is usually associated with Elaeis guineensis, Kolobopetalum chevalieri, Dioscorea preusii, Cnestis hirsutus, Tabernaemontana crassa and Funtumia africana (Tabernaemontano-Elaeetum guineensis typicum).

Direct seeding is a preferred propagation method. In a vegetative propagation study, stem cuttings rooted best (63.3%) with NAA + IBA at 100 ppm (Oni et al. 1993).

Shade or shelter: The dense canopy of A. congensis makes it a good shade tree. Ornamental: Grown as a woody ornamental tree in Kinshasa, Zaire.

Medicine: About 15 alkaloids have been isolated from the root bark, stem bark and leaves of this tree with similar uses as A. boonei as a diuretic and hypotensive.