Revision of the African genus Tessmannia (Leguminosae – Detarioideae), including seven new species.

The genus Harms (Leguminosae – Detarioideae) consists of 24 species. The genus is morphologically clearly defined and uniform. Although the number of leaflets varies from 2 (– 4) up to 36 – 48 between the species, the flower structure of the 24 species is similar. The genera Miq. and J.Léonard are closely related to the genus , but their leaflets and flowers are clearly different. All 24 species occur in tropical Africa; 18 species occur in one or more countries from Cameroon to Angola and western Tanzania; five species occur in central and eastern Tanzania; and a single species from Guinea to Ivory Coast. The species are canopy trees from rain forest, up to 53 m tall, woodland trees to 25 m tall, or woodland shrubs to 7 m tall. wood has been used for carpentry and railway sleepers and the resin has been burned to provide light. All 24 species are described here in detail. Seven species are described as new to science: Breteler & Burgt, Burgt, Breteler & Burgt, Burgt, Breteler & Burgt, Breteler & Burgt and Burgt. Three existing varieties are raised to the rank of species. (Micheli) Harms var. J.Léonard is named Burgt; Harms var. Harms is named Breteler & Burgt; and Harms var. J.Léonard is named (J.Léonard) Burgt. is described as new to science 133 years after the type specimen was collected; this type is probably the oldest herbarium collection ever made of a species. Black and white line drawings are presented of the seven newly described species and the three varieties raised to species level. A key to the species and a table listing the important morphological differences are included. All species are preliminarily assessed according to IUCN categories and criteria: one species is Critically Endangered, nine species are Endangered, seven species are Vulnerable, and seven species are Least Concern.