438 



7. (a) Pyxidium globose . . . . . . iiobilis. 



(6) Pjxidium eloiig-ated . . . . . . excelsa. 



((liameter of the fruit according- to tlio size of the fruit) 



8. Cortex of the fruit rougli, thick and iinich 



lentieellated . • . • • • ■ . . . nobilis. 



U. Opercular oi>enin<( small, wi(hMiing consider- 

 ahly inwards; or \dtli iioarl)' straiglit walls 

 narrowing slig-htly at the inner end . . ^tixcd excelsa 



and nobilis. 



10. {(I) 0])erculuni conical with a sharp point: 



{b) Operculum cylindrical llattenod at the t<)p ^Jli.xcd excelsa 



ajid nobilis. 



11. Calyx tri(k'ntatc . . . . . . . . cxceL-a. 



12. Cortex of the fruit ci'acks but does not peel off 



if the fruit is Jiandled . . . . . . Mixed excelsa 



and nobilis. 

 lo. Operculum falls into the ca\"ity of tlie fruit nol)ilis. 

 Ik Cavity of ihv finiit unicellular on witlieriug of 



the septa . . . . . . . . . . nobilis. 



G. B. Desiimukh. 



THE CORRECT BOTANIC NAMES FOR THE WHITE 



AND THE YELLOW GUINEA YAMS. 



In the Gardens' Bulletin (thi.s volume Xo. 3, 191S, pp. 8^-91) 

 short notes were g-iven upon the al)ove named two West African 

 Dioscoreas, being important foods of many millions of Negroes. 

 In it the identity of the second with Dioscorea cayenensis was stated ; 

 butfno latin name was used for the first; and the purpose of re- 

 turning to the subject here is to suggest that it is D. rottindala, 

 I'oiret (Encyclopedie methodique, sup])lement, vol. Ill, 1813, p. 

 139). D. rotundata was described upon a Bpecimen from the New 

 World : but that Poiret could arri\e at describing an African plant 

 as West Indian is very easily understood. 



The White Guinea Yam is grown in West Africa from Sierra 

 Leone to Angola in great quantities. It is in the ground for eight 

 months of the year, at the end of which period the dug tubers are 

 stored in racks in the villages for consumption as long as tliey can 

 be got to rest. 



Having a wide area and great importance, it is raised in a 

 cousidera'ble number of races, nineteen of whicli, grown in Nigeria, 

 are figured here from photographs taken by Mr. J. Hutc;hinson of 

 the Eoyal Botanic Gardens, Kew. Some of these races are earlier 

 than others, and used for prolonging the season; come are more 

 palatable; som.e heavier yielders, etc.: but of their qualities at 

 present indications only are available. 



