THE GENUS BORBONIA LINN. (LEGUMINOSyE), 



By E. p. Phillips. M.A., D.Sc, F.L.S., 

 Division of Botany, Pretoria. 



With I Map mid Plates XXXIV-XXXVIII. 



Read July ii, 1920. 



The genus Borbonia was founded by Linnaeus in 1737. and 

 in his " Species Plantarum " he described four species, and 

 again described the genus in 1743. The first important pub- 

 Hcation on the genus appeared in De Candolle's " Prodromus," 

 where eleven species are described, nine of which are still recog- 

 nised. Bentham in 1843 described two new species, B. latifolia 

 and B. complicata, but it was not until the publication of the 

 " Flora Capensis " that the genus was again monographed. 

 Harvey gives a key to, and describes 13 species, and brings 

 together the synonymy, and I have not had any occasion, after 

 examining all the available material in the South African her- 

 baria, to sink any of the species described by him. 



The genus Borbonia is closely related to Rafnia, and 

 Bentham and and Hooker distinguish the two genera as fol- 

 lows : — 



Borbonia: Calyx-lobes equal, acute or pungent. Vexillum 



villous. Legume acute. Shrubs or suftrutices with 



many-nerved leaves. 

 Rafnia: The lower calyx-lobe smaller than the others. 



Petals glabrous. Legume acute. Shrubs or suffrutices 



with one-nerved leaves. 



Harvey in his Key also uses the character of the calyx in 

 separating Borbonia from Rafnia. In the material examined 

 I find, however, that in two species, namely, B. crenata and B. 

 parwflora',. the calyx-lobes are not equal, but that the abaxial 

 lobe is longer than the others, while in B. leiantha all the petals 

 are over glabrous. The leaves especially in texture and venation 

 at once determine into which genus a species should go. All 

 the species of Borbonia, with the exception of B. villosa, have 

 very rigid leaves with three to many nerves, while in Rafnia 

 the leaves are leathery, not firm and rigid, and have only a mid- 

 rib. 



A few species of Aspalathus, as A. corymb osa E. Mey and 

 A. tenuifolia D. C, belonging to the section Terminales, have 

 simple leaves, but in these the pods are obliquely ovate at the 

 base, a character which at once distinguishes them from species 

 of Borbonia, whose pods are equal at the base. In B. mono- 



