364 



* 



p. 323), and in another form was redescribed by Poiret in 1813 as 

 D. roiundata (Ericyc. Meth. SuppL vol. iii. p. 139). Maycock in 

 1830 regarded the armed and the unarmed conditions of D. caye- 

 nensis as specifically distinct, treating the former as I), aculeata, 

 Linn., and the latter as D. sativa, Linn. (Flor. Barbad. 

 pp. 389, 390). According to Grisebach (Flor. Brit. West 

 lad. p. 587, the species described by Kunth in 1850 as 

 D. Better oana (Erium. vol. v. p. 381) is also D. caye- 

 nensis. According to Kunth, Balbis had formally pro- 

 posed the adoption of P. Browne's determination of 1756 and 

 had named the species D. aculeata. Kunth appears to have 

 doubted whether the D. cayenensis described by Grisebach in 

 1842 (Flor. Bras. vol. iii. p'. 33) be really the species described 

 by Lamarck, and the statement by Grisebach that in his plant 

 the stamens are attached at the apex of a corolla tube certainly 

 justified Kunth' s caution. On the other hand the agreement in 

 other respects, and particularly the reference by Grisebach to an 

 error in the original description, which shows that the firm and 

 glistening bract and bracteoles were mistaken by Lamarck for a 

 calyx, render it probable that Grisebach' s plant is really that of 

 Lamarck. Grown largely, as its name implies, in former days 

 to provide food for Negro slaves in the West Indies and in South 

 America, it is possible that this plant may not be a native of 

 the New World, but may have been shipped from Africa as food* 

 for those who had to endure the horrors of the middle passage 



and did not all survive. In 189G TJline definitely claimed it as 



an Old World plant. It certainly is not Asian, and if it be 

 African — it is very closely allied to the African D. prehensilis — 

 TTline has not indicated where or by whom it has been collected 



* Clusius has referred in 1601 (Rar. PI. Hist. lib. iv. p. lxxix.) to a specific 

 instance of this practice. A consignment of slaves purchased in the island 

 of S. Thome, off the Gaboon coast, in 1596, was being shipped to Lisbon for 

 resale. The ships on which the slaves were to be sent all came to Walcheren 

 in Holland. Through Parduyn, a burgess, and Roels, a physician of 

 Middelburg, Clusius obtained specimens of the Dioscorea tubers intended as 

 food for these slaves on the voyage. Clusius found that they were of two 

 sorts. His account of them is interesting, but unluckily his evidence is 

 negative so far as the origin of D. cayenensis is concerned. One kind had 

 the name Ignarne or Inhame; the description tallies with that of some race 

 of D. alata, Linn. In 164-8 there appeared a description by Marcgraf. under 

 the name Inhame de S. Thome, of D. alata as grown in Brazil. We may 

 therefore feel certain that this Inhame of Clusius really was the ' Greater 

 Yam/ But the ' Greater Yam ' originated in Asia and all we learn from 

 Clusius is that by the end of the sixteenth century this Asiatic species had 

 reached West Africa. The second kind was also termed Inhame by the 

 Portuguese merchant who handed the tubers to Parduyn. But Clusius had 

 learned somehow that others termed this second kind Yearn Peru. Yearn is 

 an African name for an edible Dioscorea. But while it may be assumed 

 that those who used the name were aware of this fact, the qualifying term 

 shows that in their judgment the plant was not the African species to which 

 the name properly belongs but an exotic which they believed, rightly or 

 wrongly, to be a native of South America. The African Akamte D. latifolia, 

 Benth., a Yam nearly allied to, if not indeed a variety of I). hnlhifera Linn. 

 The name has reached the West Indies, where the cultivated D. bnlbifera is 

 known as Acorn. But both in Africa and in th* New World Yearn or Aham 

 or Acorn connotes a member of the section Opsophyton and is not applied to 

 any species of the section E ' nantiophyllum, to which both D. alata and 

 D. cayenensis belong. 



