A Taxonomic Study on Dioscorea of Taiwan － Dioscorea cumingii
山羊百科，林文智老師的植物、山岳、攝影紀錄
- Chun Kuei Liao chunkuei.liao@gmail.com 2000/06
7. Dioscorea cumingii Prain & Burkill in Journ. & Proc. Asiat. Soc. Bengal n.s. 4:449. 1908; Merrill, Enum. Philipp. Fl. Pl. 216. 1925; Burkill in Fl. Malesiana ser.1. 4(3):317. 1941; Liu, T. S. & T. C. Huang, Bot. Bull. Acad. Sin. 3(2):136. 1962; Liu, T. S. & T. C. Huang in Fl. Taiwan 5:104. 1978.
－Dioscorea codonopsidifolia Kamikoti in Trans. Nat. Hist. Soc. Fromos. 25:115. 1935; Nemoto, Fl. Jap. Suppl. 1084. 1936; Liu, T. S. & T. C. Huang, Bot. Bull. Acad. Sin. 3(2):138. 1962; Liu, T. S. & T. C. Huang in Fl. Taiwan 5:102. 1978.
－Dioscorea heptaphylla Sasaki in Trans. Nat. Hist. Soc. Formos. 21:147. 1931; Nemoto, Fl. Jap. Suppl. 1084. 1936.
－Dioscorea pentaphylla L. Sp. Pl. 1031, 1753; Ting, C. T., M. C. Chang & P. P. Ling. in Fl. China 16(1):95, f.28. 1985 (p. p.).
HABIT DESCRIBE
A scandent, herbaceous vine from perennial tuber, up to 15m long; underground tubers, irregular ovate or oblate; epidermis brown; flesh white or slightly yellow; aerial stems terete, ca. 1-2 cm in cross-section, sinistrose, pubscence, prickly, sometimes woodly near base of stems, green or brown. Leaves alternate, palmately compound, chartaceous, pubscent, prickly; petiole 7-10(17.5) cm long, twisted, pulvinus at base, semiteres, sulcated above; leaflets 3-7, pinnately veined; veins convax on both surfaces; central leflets, obovate, narrowly obovate or oblanceolate, ca. 6.5-11(20) cm long, ca. 2-5(7) cm wide, acuminate and caudate at apex, cuneate or attenuate at base, with density pubescence on upper surface, 7-8 pairs later nerved; laternal leaflets, obovate or narrowly obovate, ca. 5.5-12 cm long, ca. 2-5 cm wide, caudat-acuminate at apex, oblique at base, 5-6 pairs later nerved; petiolete 0.6-1.1(1.7) cm long, ca. 3.6 mm thick, density pubscent.
Staminate inflorescence axillary, pendulous, racemes compound to paniculiform, up to 40 cm long; coverd with density pubscent on rachis and flowers, with a palmately bract; bract filiform, ca. 4 mm long, pubscent; racemes ca. 1.3-1.6 mm long, ca. 5 mm wide, with up to 20 flowers, with 1 bractole on base of rachilla; bractoles ovate, ca. 2 mm long, ca. 1 mm wide, acuminate and caudate at apex, slightly incurved. Male flowers globose, ca. 2 mm in diameter, 2-bracted; bracts deltoid, ca. 1.3 mm long, ca. 1.2 mm wide, acute at apex, round at base; pedicel ca. 0.35 mm long, 0.3 mm thick; outer perianth-segments , deltoid, ca. 1 mm long, ca.0.9 mm wide, acute at apex, pubsent on outside surface, glabrous on inside surface; inner perianth-segments ovate, ca. 0.8 mm long, 0.5 mm wide, acuminate at apex, glabrous; receptacle ca. 1 mm tall, ca. 1.8 mm thick; stamens 3, insert at base of outer perianth-segments, filaments terete, ca. 0.1 mm long, 0.1 mm thick, anthers, elliptic, ca. 0.36 mm long, 0.15 mm wide, dorsifixed, obtuse at apex, longitudinally dehiscent , 2-celled; staminodia 3, insert on the base of inner perianth-segments, stipes, terete, ca. 0.2 mm long, upper parts ovate, ca. 0.46 mm long, obtus at apex, flattened; pistillodium, rudimentary, tripterous, ca. 0.5 mm long, 0.4 mm wide. Pistillate inflorescence , axillary, racemose, 1-2 together, pendulous, pubscent. Female flowers, 2-bracted; perianth -segments similar to male flowers; ovary inferior, trignous, ca. 6 mm long, 2 mm wide, 3-celled; ovules 2, pendulous in each cell; pedicles reflexed after pollination. Fruit capsulate, tripterous, elliptic, ca. 3.5-5 cm long, ca. 2-2.5 cm wide, obtuse at both ends, fleshy or coriaceous in dry, green in mature or dark-brown in dry; stiple reflexed. Seeds 2 in each cell, ca. 9 mm long, ca. 4.5 mm wide, bearing in upper of central axial, with terminal wing extending to base of fruit.
Distributed in Pillppines and Taiwan.
The species is flowering from April, and fruiting May to September.
TYPIFICATION. Phillppines: Batangas, Cuming 1469.
SPECIMENS EXAMINED
SPECIMENS EXAMINED. Taipei city: Tatunshan, Kamikoti s.n. in 1943 (TAI, Type coll.) Lanyu: －, C. E. Chang 2828, 10294, 16416, 19239 (PPI); S. Sasaki s.n. in 1926 (TAI 30862, 30863, 30864, 30865, 30866, 30867, 30868, 30869, 30870, 30872, 30873); Chungaiahiao, C. K. Liao 1069 (NSYSU); Chingsheishan, C. E. Chang 11599; Huntoushan, T. C. Huang & M. T. Kao 5198 (TAI); Huntoutsun, T. C. Huang & M. T. Kao 9230 (TAI); Langtao, C. E. Chang 14825 (PPI); Tasenshan, C. E. Chang 19674 (PPI); Tienchih, T. C. Huang & M. T. Kao 16012 (TAI), S. F. Huang & Y. C. Hsu 4692 (TAI); Yunghsingshan, C. L. Yeh 821(PPI).
