A Revision of the African Species of Epilobium

Abstract

There are in Africa 10 native species of Epilobium, one of Circaea, and between 8 and 12 of Ludwigia (including Jussiaea), depending upon how many species are considered native. These three genera include all native African species of Onagraceae. Four sections of Ludwigia, cornprising a total of five species, and one fairly distinctive group of Epilobium are the most characteristic African groups. Despite the fact that H. Perrier de la Bathie (in Humb., FI. Madagasc., Oenotheracs : 1-26, 1950) considered all three of the species of Epilobium that he recognized and four of the 11 species of Ludwigia (including Jussiaea) to be endemic to Madagascar, there are in my opinion no Mascarene endemics in the family Onagraceae and nothing to suggest any great antiquity for the family on that island. This observation agrees with the general pattern for the family in Africa in suggesting that plants of this family are relatively recent arrivals on that continent. Indeed this generality could be extended to apply to the Old World as a whole, where there is no endemic genus of the family (as opposed to 16 endemic genera and 2 endemic tribes—Lopezieae and Onagreae—in the New World, principally in Mexico and the western United States) and relatively few endemic sections or subgenera. The ten African species and one subspecies of Epilobium recognized are described, and a key provided.