A Taxonomic Study on Dioscorea of Taiwan － Dioscorea japonica

山羊百科，林文智老師的植物、山岳、攝影紀錄

• A Taxonomic Study on Dioscorea L. ( Dioscoreaceae ) of Taiwan

Chun Kuei Liao　chunkuei.liao@gmail.com 2000/06

12. Dioscorea japonica Thunb. Fl. Jap. 151. 1784; Miq. in Ann. Mus. Bot. Lugd.-Bat. 3:159. 1867; Matsumura & Hayata, Enum. Pl. 43:3. 1906; Kawakami, List Pl. Formos. 122. 1910; Knuth in Pflanzenr. 87(4-43):262. 1924; Yamamoto, Suppl. Icon. Pl. Formos. 3:7. 1927; Prain & Burkill, Ann. Roy. Bot. Gard. Callcutta 14(2): 257. 1939, p.105. 1938; Liu, T. S. & T. C. Huang in Bot. Bull. Acad. Sin. 3(2):143. 1962; Liu, T. S. & T. C. Huang in Fl. Taiwan 5:107. 1978; Ting, C. T., M. C. Chang & P. P. Ling. in Fl. China 16(1): 105, f.33. 1985 日本薯蕷.

－Dioscorea japonica var. kelungensis (R. Knuth) Prain & Burkill in Kew Bull. 119. 1926; Yamamoto, Suppl. Icon. 3:7. 1927; Sasaki, List Pl. Formos. 144. 1928; Nemoto, Fl. Jap. Suppl. 1084. 1936; Ohwi, Fl. Jap. 314. 1965; Walker in Fl. Okinawa & Sounth Ryukyu Isl. 320. 1976. －Dioscorea japonica var. oldhamii Uline & Knuth in Engl. Pflanzenr. 263. 1924; Yamamoto in Journ. Soc. Trop. Agr. 10:182. 1938; Liu, T. S. & T. C. Huang in Bot. Bull. Acad. Sin. 3(2):143. 1962; Liu, T. S. & T. C. Huang in Fl. Taiwan 5:107. 1978; Ting, C. T., M. C. Chang & P. P. Ling. in Fl. China 16(1): 105. 1985.

－Dioscorea japonica var. pseudojaponica (Hayata) Yamamoto in Journ. Soc. Trop. Agr. 10:182.line msc.; Liu, T. S. & T. C. Huang in Bot. Bull. Acad. Sin. 3(2):143. 1962; Liu, T. S. & T. C. Huang in Fl. Taiwan 5:107. 1978.

－Dioscorea japonica var. vera Prain et Burkill in Journ. Asiat. Soc. Bengal. 10:28. 1914; Liu, T. S. & T. C. Huang in Bot. Bull. Acad. Sin. 3(2):144. 1962.

－Dioscorea kelungensis (non Hayata) Knuth in Engl. Pflanzen. 263. 1924.

－Dioscorea pseudojaponica Hayata, Icon. Pl. Formos. 10:42,f.21. 1921; Hatusima, Fl. Ryukus 791. 1971; Walker in Fl. Okinawa & Sounth Ryukyu Isl. 320. 1976.

－Dioscorea rhipogonoides Hayata, Gen. Ind. F. Formosa. 84, 1917.

－Dioscorea rhipogonoides var. aculeata, Uline msc.

HABIT　DESCRIBE

　A scendent glabrous vine from annual tuber; underground tuber cylindrical or clavate, ca. 1-2 cm in cross-section, growing down vertically to 1 m; epidermis brown or yellow brown; flesh white; edible, never poisonous; aerial stems terete, ca. 5-8 mm thick, slender, branched, dextrorse, herbaceous, green or violet, sometimes warty near the base of stems; axillary aerial tubers , globose or irregular branched, ca. 1-3 cm long, 5-10mm in diameter, glabrous, greyish, black-brown, or brown, with reticulate lines and warts on surface. Leaves opposite or alternate near base of stems, triangular, ovate-triangular, hastate-lanceolate or sagittate-lanceolate, ca. 6-10 cm long, 2-5 (10) cm wide, acuminate or caudate or acute at apex, sagittate, hastate, auriculate, cordate, or truncate at base, sometimes 3-lobed, chartaceous, or membranous, green on both surfaces or slightly violet on lower surface; nerves (5)7-9; nerves concave on upper surface and convex at lower surface, green or sometimes violet; petioles semiterete, ca. 2-4.5 cm long, 3-5 ridged, sculcate above, green or violet, twisted and slight diltated at base.

　Staminat inflorescence axillary, spicate, 1-3 together; spikes with ca. 30 flowers, ca. 3-5 cm long; rachis slightly zigzag, yellow. Male flowers alternate on rachis, globose, ca. 1.5mm in diameter, 2-bracted; outer bract triangular, ca. 1.5mm long, 0.9 mm wide, acuminate at apex; inner bract ovate, ca. 1mm long, 0.7 mm wide, acute at apex, obtuse at base; perianths 6, yellow-greenish; outer 3 perianths widely ovate, ca. 1.7 mm long, ca. 1.5 mm wide, obtuse at apex, round at base; inner 3 perianth obovate, ca. 1.4 mm long, ca. 1 mm wide, round at apex, acute at base; stamens 6, subequal, filaments 0.8mm long, terete, anthers oblong, ca. 0.6 mm long, 0.3 mm wide, dorsifixed, longitudinally dehiscent; pistillodium rudimentary, conicus, ca. 0.4 mm tall; stigmatiform 3-lobed. Pistillate inflorescence raceme, solitary, axillary, with upward of 20 flowers; rachis ca. 10 cm long, greenish, rigid, with 3-longitudinally ridges; female flowers ca. 7 mm long, ca. 1.9 mm wide, glabrous, 2 bracted; outer bract orbicular, ca. 1.6 mm long, ca. 1 mm wide, acuminate at apex; inner bract orbicular, ca. 1.2 mm long, ca. 0.9mm wide, caudate at apex, round at base; perianths 6, yellow; outer 3 perianths widely ovate, ca. 1.3 mm long, ca. 1.1 mm wide, obtuse at apex; inner 3 perianths ovate, ca. 1.2 mm long, 0.8mm wide, obtuse at apex; staminodia 6, inserted at base of perianths, stick-like, ca. 0.13mm thick; outer 3 staminodia ca. 0.3mm long; inner 3 staminodia ca. 0.4 mm, 2-4 lobed at apex; pistillum ca. 0.9 mm tall, ca. 1.3 mm wide; stigmas 3-lobed, 2-cleft at apex; ovary inferior, green, trigonous, 3-celled; ovules 2 in each cell. Fruit capsulate, transversely elliptic, tripterous, ca. 1.8 cm long, ca. 3 cm wide, pendulous, green in mature, brown in dry, truncate or retuse at apex. Seeds 2 in each cell, orbicular, ca. 0.5 mm in diameter, membranous wing around, wing ca. 0.7 mm wide.

　Distributed in Japan, China, Ryukyus and Taiwan.

　This species is flowering from May to November, and fruiting from June to November.

TYPIFICATION: Japan: Thunb. fig. 109, 110. in Drawing of Jappanese plants.

SPECIMENS EXAMINED

SPECIMENS EXAMINED. Taipei City: Tangmingshan (Sozan), H. Shimada 1282 (TAI), S. Sasaki s.n. in 1927 (TFRI). Taipei Hsien: Hsiaochilung (littore Kelung), U. Faurie 548 (TFRI); Pihu, S. F. Huang 2970 (TAI); Shihtin, Keng & Kao 1293 1294 (TAI); Wantan, H. Hisimiza 2117 (TAI); Yehliu, T. C. Huang 10869a (TAI). Taoyuan Hsien: Lalashan(Rarazan), E. Matuda 525 (TAI); Litunshan (Mt. Rito), E. Matuda 521, 524 (TAI). Hsinchu Hsien: Sintika, Y. Simada 1079 (TFRI). Taichung Hsien: Jihyuehtan, Kudo & Sasaki 15274 (TAI); Lishan, E. Matuda 527 (TAI); Pahsienshan, S. Susuki s.n. in 1929 (TAI); Chikashanchuang-369shanchuang, T. C. Huang 7278 (TAI). Nantou: Chingshuikou, T. C. Huang 224, 1910, 1943 (TAI). Kaohsiung Hsien: Laonung, U. Mori s.n. in 1907 (TFRI). Pingtung Hsien: Likang, E. Matuda s.n. in 1917 (TAI 30911); Macha, T. C. Huang & M. T. Kao 7351 (TAI); Tamei (Mutan Hsiang), C. L. Yeh 859 (PPI). Taitung Hsien: Taimali (Tamrui), U. Faurie 550 (TFRI). Lutao: S. Sasaki s.n. in 1934 (TAI). Lanyu: Shuangshihyenshan, C. L. Yeh 807 (PPI). Hualien Hsien: Hsipan (Suiroku), S. Susuki 10507 (TAI); Tailukotashan, S. Sasaki s.n. in 1933 (TAI).