The genus contains over 50 species distributed in Africa south of the Sahara with one species occurring in Madagascar (V. madagascariensis). The centre of diversity is in East Africa (Kenya, Tanzania) and they are rare in West Africa.
Bacterial leaf symbiosis
Endophytic bacteria are housed in the intercellular space of the leaf mesophyll tissue. The presence of these bacteria can only be microscopically ascertained. The bacteria are identified as Burkholderia, which is a genus that is also found in the leaves of other Rubiaceae species.[2][3] The hypothesis is that these endophytic bacteria provide chemical protection against insect herbivory.[4]
Gousiekte
Several Vangueria species - V. latifolia, V. pygmaea, V. thamnus - are known to cause gousiekte, a cardiotoxicosis of ruminants characterised by heart failure four to eight weeks after ingestion of certain rubiaceous plants.[5]
Species in the former genus Tapiphyllum were sunk into synonymy Vangueria when a 2005 molecular phylogeneticstudy showed that the type species, Tapiphyllum cinerascens, is more closely related to Vangueria than to Tapiphyllum obtusifolium and Tapiphyllum velutinum, and that the latter two were not distinct from Vangueria.[7]
^Verstraete B, Janssens S, Lemaire B, Smets E, Dessein S (2013). "Phylogenetic lineages in Vanguerieae (Rubiaceae) associated with Burkholderia bacteria in sub-Saharan Africa". American Journal of Botany. 100 (12): 2380–2387. doi:10.3732/ajb.1300303. PMID24275705.
^Lantz H, Bremer B (2005). "Phylogeny of the complex Vanguerieae (Rubiaceae) genera Fadogia, Rytigynia, and Vangueria with close relatives and a new circumscription of Vangueria". Plant Systematics and Evolution. 253 (1–4): 159–183. Bibcode:2005PSyEv.253..159L. doi:10.1007/s00606-005-0313-9. S2CID30867982.