Bioscorea.] cxxxix. DioscoREACEiE (baker). 417 



7. D. rubig^inosa, Benth. in Hook. Niger Fl. 538. Stem unarmed, 

 twining, ferrugineo-tomentose. Leaves alternate, distinctly petiolate' 

 simple, cordate-ovate, cuspidate, 3-4 in. long, 7-9- nerved from the 

 apex of the petiole, glabrous above, ferrugineo-tomentose beneath. 

 Male flowers unknown. Female flowers in lax fascicled spikes 3-4 in. 

 long ; bracts oblong, minute. Perianth tomentose ; outer segments 

 ovate, inner oblong. Ovary obtusely trigonous, oblonff, imperfectly 

 3-celled. ^ ^ 



TTpper Guinea. Sierra Leone, Don ! 

 No specimen at Kew. 



8. D. Preussii, Pax in Engl. Jahrh. xv. 147. Stems slender, 

 climbing, unarmed, pubescent when young. Leaves all alternate, 

 distinctly petiolate, simple, cordate-ovate, cuspidate, thin, 7-9-nerved, 

 3-4 in. long and broad, glabrous above, pubescent beneath. Male 

 I'acemes fascicled in the axils of the leaves, very lax, reaching 6-8 in. 

 long ; rhachis pubescent ; bracts lanceolate,, pubescent. Perianth hairy, 

 -^^ in. long ; segments obtuse, ovate or oblong. Fertile stamens 3. 

 Female flowers and fruit unknown. 



Upper Guinea. Lagos; Abeokuta, Jruin^, 303 ! Cameroons: Yaunde, Zew/ter, 

 325 ! Zenker Sf Staudt, 413 ! and without precise locality, Preuss, 504 ! 



9. D. alata, lAnn. Sp. Plant, edit. 1, 1033. Root large, edible. 

 Stems twining, glabrous, quadrangular, 4-winged. Leaves distinctly 

 petiolate, simple, usually opposite, ovate-acuminate, deeply cordate at 

 the base, glabrous, 7-nerved from the apex of the petiole, membranous, 

 reaching 6-9 in. long. Male flowers in long slender fascicled spikes. 

 Perianth ^^ in. long ; segments lanceolate, glabrous. Fertile stamens 6. 

 Female flowers in lax spikes. Capsule glabrous, with 3 large wings, 

 1-1 J in. diam. ; axis f in. long. Seeds orbicular, winged all round the 

 nucleus. — Schum. Beskr. Guin. Plant. 447 ; Kunth, Enum. v. 387 ; 

 Hook. f. Fl. Brit. Ind. vi. 296. 



Upper Guinea. Niger Territory: Nupe, Barter, 1534! by the River Niger 

 (Quorra), Vogel ! 



irile Ziand> British East Africa : Niamniam ; at the River Nabambisso, 

 Schtceinfurth, 3712 ! 



laO'weT Guinea. Island of St. Thomas, Moller, 103 ! Quintas, b ! Angola, 

 Wehoitsch, 4030 ! 4036 ! 4044 ! 



Cultivated throughout Tropical Africa. 



10. D. colocasisefolia, Pax in Ev^l. Jahrh. xv. 145. Stems 

 climbing ; branches 4-winged. Leaves opposite, distinctly petiolate, 

 simple, ovate, acuminate, deeply sagittate at the base, 1 ft. long, 7-8 in. 

 broad, 7-nei'ved from the apex of the petiole, glabrous on both surfaces. 

 Male flowers unknown. Female flowers in branched tomentose spikes ; 

 bracts linear, tomentose. Perianth-segments ovate, obtuse, tomentose. 

 Ovary tomentose ; style very short. 



Upper Guinea. Cameroons: Victoria, cultivated under the name of " Water 

 Yam," Buchholz. Called also " Yorna," J. Braun. 

 No specimen at Kew. 



