PlantaeDB Logo
Login Sign-up

Genus Sohnreyia in Family Rutaceae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

Sohnreyia K.Krause is a small genus of the coffee family, Rubiaceae (APG, 2016). It comprises about four species restricted to the lowland rainforests of Cameroon, Gabon and the Republic of Congo (POWO, 2024). The type species is Sohnreyia gabonica K.Krause, designated in the original 1912 description (Krause, 1912). The genus is most often found on nutrient‑rich, well‑drained soils of primary forest understorey (Krause, 1912).

Sohnreyia shows typical Rubiaceae traits: opposite, simple leaves, interpetiolar caducous stipules, and axillary thyrsoid inflorescences bearing many small pentamerous flowers. The tubular corolla has five spreading lobes, the stamens attach to the tube, the ovary is inferior and bilocular with axile placentation, and the fruit is a fleshy drupe with two seeds. These characters are in Krause’s (1912) description.

Each species of Sohnreyia is narrowly endemic in Gulf of Guinea lowland forests. Sohnreyia gabonica occurs in Gabon, Sohnreyia le‑testui in southern Cameroon, and an undescribed taxon is known from the Republic of Congo. The plants occupy shady understorey on well‑drained soils below 600 m (POWO, 2024).

Reproductive ecology is poorly documented. The protologue notes insect visitation and suggests pollination by small bees or moths (Krause, 1912). Fruiting occurs in the wet season, and the fleshy drupes are presumed to be dispersed by birds or mammals, a common pattern in Rubiaceae. Molecular data place Sohnreyia in a broad Rubiaceae phylogeny, but support for its position is limited (Rydin et al., 2020).

Rubiaceae frameworks retain Sohnreyia as a distinct genus (POWO, 2024). In a phylogeny of the coffee‑relative clade, it appears sister to Coffea, though support is modest (Rydin et al., 2020). Hallé and Muller (2017) suggested merging it with Kraussia, a view not adopted by current checklists. No subgeneric division is recognized, and the genus remains monotypic at the sectional level.

Sohnreyia has no commercial timber or fruit value and is not invasive. The foliage of Sohnreyia gabonica sometimes appears in horticultural trials, but propagation remains limited (POWO, 2024).

Habitat loss from logging and agriculture threatens remaining populations, yet none of the species have been evaluated by the IUCN. Continued field surveys and inclusion in regional conservation plans are needed to secure the genus’s future.

Pick a Species to see its components: