Volume 10 > Part 1 > Year 2009 > Page 29 > Dioscoreaceae > Dioscorea

7. Dioscorea cirrhosa Lour.wfo-0000389893

Fl. Cochinch. 2: 767. 1793; Kunth, Enum. Pl. 5: 401. 1850; Prain & Burkill, J. & Proc. Asiat. Soc. Bengal 10: 31. 1914; R.Knuth in Engl., Pflanzenr. 4, 43: 288. 1924; Prain & Burkill in Fl. Indo-Chine 6: 738. 1934; Ann. Roy. Bot. Gard. (Calcutta) 14(2): 273. 1938; Hô, Câyco Viêtnam 3, 2: 929. 1993; Ding & Gilbert in Fl. China 24: 295. 2000. Fig. 13, 14.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Large forest climber to at least 20 m. Tubers solitary 10–15 by 1–2.5 cm, cylindric to clavate, perennially replaced. Indumentum absent. Stems perennial, to 6.5 mm in diam. toward base, woody and densely spiny, usually unarmed distally, terete. Leaves simple, alternate to subopposite towards base, usually opposite or subopposite on distal stems; blade elliptic-oblong to ovate-elliptic, coriaceous, 3-veined, margins entire, base obtuse to rounded, apex acute to acuminate; petioles 1.3–4 cm long; cataphylls 3–7 by 5–6 mm. ovate, coriaceous; bulbils present in some races, 35–40 by 10–20 mm, cylindric to ovate or globose; lateral nodal organs absent. Inflorescences spicate, pendent, tepals free, inserted on a discoid torus, fleshy in texture; male inflorescences simple to compound, compound inflorescences 1(–2) per axil, simple/partial inflorescences 1–3 per axil, peduncles 3–4.2 mm long, axes 1.5–5 cm long; female inflorescences simple or compound, compound inflorescences 1 per axil, simple/partial inflorescences 1(–2) per axil. Male flowers with outer tepals 1.8–2.1 by 1.4–1.8 mm, oblong to obovate-oblong, inner tepals 1.6–1.9 by 1.2–1.4 mm, obovate, thickened at base and along ventral midrib, stamens 6. Female flowers as in Fig. 14A–G. Capsules as in Fig. 14H, J, 22–35 by 35–62 mm. Seeds 5–6 by 4–6 mm, orbicular- to ovoid-lenticular, wings 22–26 by 17–23 mm, extending all around seed margin.

Thailand : NORTH-EASTERN: Loei (Phu Kradueng, Phu Luang); EASTERN: Chaiyaphum (Phu Khiao), Nakhon Ratchasima (Khao Yai).

Distribution : C & S China to Vietnam (type), and Laos. Two specimens from peninsular Thailand may also belong to this species, WILKIN 853 (sterile) from Khao Pu Khao Ya National Park and Kerr 11909 immature male flowers) from Lang Suan.

Ecology : Restricted to hill evergreen forests, 975–1,300 m alt. Flowering: February, April; fruiting: July–December.

Uses: The tuber is used in China and Vietnam as a source of a tannin for tanning cloth and fishing nets (for example), but no record of a use in Thailand.

Conservation Status: IUCN red list category LC (IUCN 2001).

Notes: Dioscorea intempestiva Prain & Burkill falls within the range of variation of this species; the ecological attributes of both taxa are identical. The type of D. intempestiva (Poilane 10879, holotype -P) was collected in Vietnam. The typification of D. matsudae Hayata and D. formosana R.Knuth was discussed by Ding & Gilbert (2000). These Chinese names were not dealt with in this study, but it should be noted that Thai populations of D. cirrhosa have prickly stems as described in the protologue of D. formosana.