349 



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Presl also, at least in intention, excluded the West Indian species 

 of Plumier, D. sativa, Linn. [4] ; following- Willdenow, he 

 referred this to D. piper i folia, Humb. and Bonpl. But his action 

 in this respect was imperfect; he cited Gaertner's figure and 

 description under D. sativa Linn., without observing that the 

 plant of Gaertner is also that of Plunder, so that according to 

 Presl, D. sativa, Linn. [4], finds a place under two different 

 .species. What the actual species which Haenke collected and 

 Presl described as D. sativa may be, is not clear; it certainly is 

 no part of D. sativa, Linn., since none of the elements of that 

 aggregate occur in Peru. It does not appear even to be identical 

 with D. sativa, Rodsch. non Linn. (1796); at all events no 

 Peruvian specimens of that species, which is D. lit tea, Meyer 

 (1818), have so far been met with by us. 



In 1830 Haycock (Flor. Barb ad. p. 390) restricted the name 

 1). sativa to a single West Indian cultivated Dioscorea, other 

 than D. alata, Linn., and other than D. bulb if era, Linn. May- 

 cock excluded from D. sativa, the ' Wild Yam ' of Browne 

 I.e., footnote), which Willdenow had included, and in effect 

 confined the name D. sativa to the Volubilis nigra, radice tube- 

 rosa compressa, whose identity with D. cayenensis, Lamk, is 

 proved by Sloane's original specimen. But I), cayenensis some- 

 times is unarmed, at other times has the stem beset with prickles, 

 and ^faycock was led to regard these two states of this species as 

 distinct. As a consequence he referred the armed condition of 

 the species to I), aculeata, Linn., and thereby separated the 

 Volubilis nigra, radice tuberosa compressa of Sloane from the 

 Dioscorea foliis cordatis, caule tereti aculeate of Browne (I.e. 

 p. 389, footnote). Maycock has, however, explained that he had 

 no opportunity of informing himself how far the Yams actually 

 cultivated in Barbados are distinct species or only varieties 

 (I.e. p. 391, footnote), so that we do not know how far his judg- 

 ment as to the difference between the plants of Sloane and Browne 

 might have been modified by field-study. But Maycock at 

 least shares with Blume the merit of having appreciated inde- 

 pendently that, for the sake of convenience, if for no other 

 reason, the name/?, satira should be applied to a cultivated Tom, 

 and should, if possible, be restricted to only one Yam. 



In 1831 Bunge used the name 1). sativa (Enum. PI. Chin. p. 64) 

 for a cultivated Chinese Yam which differs from the cultivated 

 -Japanese Yam taken for T>. sativa by Thunberg in 1784, and also 

 differs from all the plants included under D. sativa by Linnaeus. 

 D. .satira, Bunge, is the cultivated Yam known in Japan as 

 ' Tsukne-imo, J first named by Thunberg in 1784. Thunberg' s 

 name, D. opposita (Flor. Japan, p. 151), having been overlooked, 

 this garden plant was described by Turczaninow in 1837 as D. 

 polystaehya (Bull. Imp. Soc. Nat. Mosc. vol. xi. n. 7. p. 158). 

 This name was in turn overlooked and the species was redescribed 

 by Decaisne in 1854 as D. Batatas (Rev. Hort. ser. 4. vol. iii. 

 p. 243). What is a distinct cultivated form of the same species, 

 not however differing sufficiently from the type to be regarded 

 even as a variety, waa described by Carriere in 1865 as D. Decais- 



veana (Rev. Hort. 1865, p. 111). 



In 1832 the name D. satira, Herb. Madras, waa employed by 



