Dioscorea. | CXXXIX. DIOSCOREACEA (BAKER). 417 
7. D. rubiginosa, Benth. in Hook. Niger Fl. 588. 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, oblong, imperfectly 
3-celled. 
Upper Guinea. Sierra Leone, Don! 
No specimen at Kew. 
8. D. Preussii, Pax in Engl. Jahrb. 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 
racemes fascicled in the axils of the leaves, very lax, reaching 6-8 in. 
long ; rhachis pubescent; bracts lanceolate, pubescent. Perianth hairy, 
zz in. long; segments obtuse, ovate or oblong. Fertile stamens 3. 
Female flowers and fruit unknown. 
Upper Guinea. Lagos; Abeokuta, Irving, 103! Cameroons: Yaunde, Zenker, 
325! Zenker & Staudt, 413! and without precise locality, Preuss, 504! 
9. D. alata, Linn. 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 51, in. long ; segments lanceolate, glabrous. Fertile stamens 6. 
Female flowers in lax spikes. Capsule glabrous, with 3 large wings, 
1-1} in. diam. ; axis } 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 ! 
Nile Land. British East Africa: Niamniam; at the River Nabambisso, 
Schweinfurth, 3712! 
Lower Guinea. Island of St. Thomas, Moller, 103! Quintas, B! Angola, 
Welwitsch, 4030! 4036! 4044! 
Cultivated throughout Tropical Africa, 
10. D. colocasizfolia, Pax in Engl. Jahrb. 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-nerved 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. 
VOL. VII. 2E 
