80 ORIGIN OF CULTIVATED PLANTS. 



confusion he made between the manioc and the yam, 

 D. Clifortiana, Lam., grows wild in Peru^ and in 

 Brazil,^ but it is not proved to be cultivated. Presl says 

 verosimiliter colitur, and the Flora Brasiliensis does 

 not mention cultivation. 



The species chiefly cultivated in French Guiana, 

 according to Sagot,^ is Dioscorea triloha, Lam., called 

 Indian yam, which is also common in Brazil and 

 the West India Islands. The common name argues a 

 native origin, whereas another species, D. cayennensis^ 

 Kunth, also cultivated in Guiana, but under the name of 

 negro-country yaon, was most likely brought from Africa, 

 an opinion the more probable that Sir W. Hooker likens 

 a yam cultivated in Africa on the banks of the Nun and 

 the Quorra,- to D. cayennensis. Lastly, the free yaon 

 of Guiana is, according to Dr. Sagot, D. alata introduced 

 from the Malay Ai^chipelago and Polynesia. 



In Africa there are fewer indigenous Bioscorece than 

 in Asia and America, and the culture of yams is less 

 widely spread. On the west coast, acQording to Thon- 

 ning,^ only one or two species are cultivated ; Lockhardt ^ 

 only saw one in Congo, and that only in one locality. 

 Bojer"^ mentions four cultivated species in Mauritius, 

 which are, he says, of Asiatic origin, and one, D. hul- 

 hifera, Lam., from India, if the name be correct. He 

 asserts that it came from Madagascar, and has spread 

 into the woods beyond the plantations. In Mauritius 

 it bears the name Caonbare marron. Now, camhare 

 is something like the Hindu name kam, and niarron 

 (marroon) indicates a plant escaped from cultivation. 

 The ancient Egyptians cultivated no yams, which argues 

 a cultivation less ancient in India than that of the colo- 

 casia. Forskal and Delile mention no yams cultivated 

 in Egypt at the present day. 



To sum up : several Bioscorece wild in Asia (especially 



^ Hsenke, in Presl, Eel, p. 133. " Martins, Fl. Bras., v. p. 43. 



3 Sagot, Bull. Soc. Bot. France, 1871, p. 305. 



4 Hooker, Fl. Nigrit, p. 53. 



5 Scliumaclaer and Thonning, Beslc. Guin, p. 447. 



^ Brown, Conrjo, p. 49. ' Bojer, Hortus Ilauritianus. 



