32 CIRCULAR NO. 124, BUREAU OF PLANT INDUSTRY. 



pointed out. The lobing of the leaves is very variable and commonly 

 occurs in cultivated Vigna i^ineni^is, especially when in poor soil. 



Vigna triloba occurs mainly south of the P^quator, where it is appar- 

 ently never cultivated. However, specimens collected by Dr. J. M. 

 Dalziel in the Katagum District, Northern Nigeria, May, 1908, wliich 

 seem indistinguishable from Vigna triloba, bear the legend ''Common 

 cultivated bean of the fields." 



In Angola, forms of Vigna triloba with narrow leaflets occur. Such 

 specimens are represented by Welwitsch's No. 2262 from Loanda 

 and No. 2263 from Pungo Andongo. On the former of these Wel- 

 witsch has recorded "a herb persisting for several years but scarcely 

 ])erennial," and on the latter "a herb enduring apparently for several 

 years." Gossweilcr has more recently made collections in the same 

 region. His No. 4802 from Grongude, apparently identical with Wel- 

 witsch's No. 2262, is stated to be "a perennial many-leaved vine, ^\dth 

 large blue flowers," while liis No. 1534 from Penodo, quite the same 

 as Welwitsch's No. 2263, bears the legend "u perennial cUmber." 



Differing from this narrow-leaved plant mainly in being pubescent 

 is a form occurring in Natal, Transvaal, etc., which was called ScytO/- 

 lis protracta by E. H. F. Meyer. All recent botanists have consid- 

 ered tliis only a form of Vigna triloba. 



Another form with still narrower leaflets and lacking the pubes- 

 cence has been named Vigna triloba stenophylla Harvey and Sonder.^ 



In the light of present evidence it is not clear that Vigna triloba 

 is specifically distinct from the wild Vigna sinensis of Africa. On 

 the other hand, the statements of Welwitsch and of Gossweiler that 

 Vigna triloba persists more than one year indicate that it is different, 

 in this respect at least, from Vigna sinensis. The trilobed leaflets 

 as a mark of distinction can not be depended upon, yet in classifying 

 specimens this is the only evident character. In the herbarium at 

 Kew are specimens of both species', so far as this distinction may be 

 depended upon, collected by Dr. J. M. Dalziel in the Katagum Dis- 

 trict, Northern Nigeria. The one referable to Vigna triloba is said 

 to be ''the common '6ultivated bean of the fields,'* wliile no data 

 regarding the habitat, of the other are recorded. 



There is scarcely room for doubt, however, from the ani})le herba- 

 rium material, that the ^ifrican plant with blacldsh scabrous pods 

 and scabrous leaflets found wild over a great area and occasionally 

 cultivated is the original wild form of our cultivated cow^ea. This 

 conclusion is further confu-med by a study of comj^arative cultures 

 and the fact that hybrids between the wild plant and the cowpea 

 are readily obtained. Whether Vigna triloba is to be considered a 

 distinct species can hardly be decided in the light of j^resent evidence. 



' Harvey, W. H., and Sender, O. W. Flora Capensis, v. 2, Dublin, 1861-2, p. 241. 

 I (Mr. IL'4] 



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