2, A Synopsis of the Dioscoreas of the Old World, 



Africa excluded, with descriptions of new- 

 species and of varieties. 



By D. Prain and I. H. Burkill. 



The paper on Dioscorea, here offered, is intended to serve 

 two purposes : (1) to publish in the requisite form diagnoses of 

 certain new species and varieties, and (2) to make immediately 

 available a key to this difficult genus. In the Annals of the 

 Royal Botanic Gardens, Calcutta, our detailed monograph 

 will appear, with rather more than one hundred plates and 

 a full account of the synonymy, distribution, uses and rela- 

 tionship of the species here briefly enumerated. 



The reader will observe that this paper anticipates the 

 publication, in Mr. Elmer's Leaflets of Philippine Botany, of 

 several diagnoses l : he may also note that the correct positions 

 of Dioscorea polystachya, Turcz., D. deleteria, Noronha, D. 

 goeringiana, Kunth, and D. vilis, Kunth, are not given as we have 

 not decided what they are. D. polystachya is presumedly near 

 to D. japonica : it was imperfectly described by Turczaninow : 

 but his type is preserved in the St. Petersburg herbarium, and we 

 trust that we may shortly be able to examine it. D. goeringiana 

 was described from inadequate material (now apparently lost) : 

 we think that it belongs to the section Stenophora. D. vilis, 

 described from immature material, is one of the section Enan- 

 tiophyllum. 



PART I. 



A Key to the Species. 



Section 1. Borderea. — Tuber globular, crowned with 

 a dense tuft of scales, apparently growing very slowly forward, 

 and dying behind, but its exact nature has not been investi- 

 gated. Stem short, not supporting itself by twining, but 



sometimes flexuous. Leaves simple, entire. Male-flowers in 

 spreading racemes : perianth-members just united : the stamens 

 inserted on the bases of the perianth-lobes : filaments simple. 

 Female flowers 1 — 2 together. Seeds without wings, in abbre- 

 viated erect capsules. 



Only species 



1. pyrenaica 



The 



Volume V of Mr. Elmer's Leaflets of Philippine Botany. 



