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FOC | Family List | FOC Vol. 24 | Dioscoreaceae | Dioscorea

6. Dioscorea sect. Botryosicyos (Hochstetter) Uline in Engler & Prantl, Nat. Pflanzenfam. 2(5): 84. 1897.

复叶组 fu ye zu

Botryosicyos Hochstetter, Flora 27(Bes. Beil. Bd. 1): 3. 1844.

Rootstock of perennial tubers irregular in shape. Stem twining to left. Bulblets present or absent. Leaves alternate, palmately 3--9-foliolate; leaflets ± orbicular to narrowly lanceolate, pinnately veined, margin entire; lateral leaflets similar to central one. Male inflorescences of spikes or racemes clustered or in panicles. Flowers solitary, pedicellate; bract and bracteole(s) borne on pedicel or at base of perianth, often forming an involucel around flower; perianth lobes connate at base; stamens usually 3, alternating with 3 staminodes. Female spike occasionaly branched. Capsule reflexed at maturity, longer than wide. Seeds inserted near apex of capsule; wing pointing toward capsule base.

About 30 species: Africa, Asia, Europe; nine species (four endemic) in China.

Prain and Burkill treated the members of this section within Dioscorea sect. Lasiophyton but the differences in leaflet venation, male bracts, stamen number, and chemistry justify the resurrection of D. sect. Botryosicyos.

1 Stem not prickly.   (2)
+ Stem and/or petioles prickly, particularly toward base of plant.   (4)
2 (1) Bulblets black at maturity, globose, glabrous, smooth; leaf blade glabrous or sparsely hairy along veins   29 D. melanophyma
+ Bulblets not black at maturity, not globose, rough or with warty projections; leaf blade ± uniformly hairy.   (3)
3 (2) Stem hairs spreading; male flowers 2--3.5 × 2--3 mm; tubers ovoid, cork brown   30 D. kamoonensis
+ Stem hairs appressed; male flowers 1--2 × ca. 1.5 mm; tubers cylindric, cork yellowish white   31 D. delavayi
4 (1) Capsule 1.8--2.5 cm; leaf blade abaxially sparsely hairy or glabrous.   (5)
+ Capsule 3.5--7 cm; leaf blade abaxially hairy, sometimes densely so.   (6)
5 (4) Capsule not black at maturity; leaflets 3, suborbicular to broadly obovate; tubers with 3--10 or more branches, each end enlarged into an ovoid or ellipsoid tuber   32 D. menglaensis
+ Capsule black at maturity; leaflets 3--7, obovate to oblanceolate; tubers simple, long ovoid   33 D. pentaphylla
6 (4) Whole plant densely grayish white tomentose   34 D. esquirolii
+ Whole plant white or brown pubescent.   (7)
7 (6) Leaflets ovate-elliptic, abaxially densely white pubescent   37 D. xizangensis
+ Leaflets lanceolate, abaxially sparsely hairy, glabrescent.   (8)
8 (7) Leaflets leathery   35 D. scortechinii var. parviflora
+ Leaflets ± herbaceous   36 D. cumingii

Lower Taxa


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