314 



DiOSCOREACEAE 



5B. Staminodia absent in the starainate flowers; leaves broadly deltoid-lanceolate to narrowly ovate-deltoid, 8-15 cm. long, deeply 



cordate, the basal margins often imbricate; staminate flowers pedicellate 5. D. asclepiadea 



B. Fertile stamens 6. 

 6A. Seeds winged on one side. 



7A. Leaves entire, glabrous; flowers fully expanding 6. D. to\oro 



7B. Leaves palmately lobed, usually pilose; flowers campanulate, not fully expanding 7. D. nipponica 



6B. Seeds winged all the way around. 



8A. Leaves entire; staminate flowers rather loose, distinctly pedicelled 8. D. tenuipes 



8B. Leaves palmately lobed; staminate flowers dense, sessile to short-pedicelled. 



9A. Leaves usually pilose; staminate flowers short-pedicelled 9. D. quinqueloba 



9B. Leaves glabrous, sometimes minutely papillose on the nerves beneath; staminate flowers sessile 10. D. septemhba 



1. Dioscorea japonica Thunb. Yama-no-imo. Root 

 fleshy, cylindric, elongate, perpendicular; stems elongate, 

 branched; leaves opposite, sometimes alternate, cordate at base, 

 long-petioled, narrowly oblong-deltoid, 5-10 cm. long, 2-5 cm. 

 wide, long-acuminate, green, glabrous; inflorescence 1- to 

 3-nate in leaf axils, spicate, short-peduncled; flowers white, the 

 pistillate pendulous, loosely few-flowered, the staminate erect, 

 rather loosely many-flowered, sessile; stamens 6; capsules 

 broadly elliptic, 1.2-1.4 cm. long, about 2 cm. wide; seeds 



broadly wing-margined. Aug. Wooded foothills; Honshu, 



Shikoku, Kyushu. 



2. Dioscorea batatas Decne. D. polystachya sensu auct. 



Japon., non Turcz. ^Naga-imo. Root fleshy, cylindric to 



flabellate, perpendicular; stems usually purplish; leaves long- 

 petiolate, nearly deltoid-ovate, acuminate, broadly cordate and 

 often auriculate at base, purplish on petioles and nerves, with 

 bulbils in axils; inflorescence spicate, 1- to 3-nate, in leaf axils; 

 flowers sessile, white, the staminate erect, rather loosely many- 

 flowered, the pistillate pendulous, loosely few-flowered; sta- 

 mens 6; capsules obovate-orbicular. Aug.-Sept. Hok- 

 kaido, Honshu, Shikoku, Kyushu; frequently planted. 



Korea, China, and Formosa. 



3. Dioscorea bulbifera L. D. sativa sensu auct. Japon., 

 non L.— — NiGA-KASHU. Tuberous root depressed-globose, 

 5-8 cm. across; stems elongate, branched; leaves alternate, 

 long-petiolate, depressed-cordate or deltoid, glabrous, abruptly 

 acuminate, entire, with bulbils in the axils; staminate spikes 

 1- to 3-nate, in leaf axils, short-pedunculate, rather densely 

 many-flowered; flowers sessile, the tepals linear-lanceolate, as- 

 cending, rather thick, 2.5-3 mm. long; stamens 6. Aug.- 

 Sept. Honshu (Chiigoku Distr.), Shikoku, Kyushu.- 



Forma domestica (Makino) Makino & Nemoto. D. saliva f. 



domestica Makino Kashu-imo. Cultivated for the edible 



bulbils and tuberous roots. ^Forma spontanea (Makino) 



Makino & Nemoto. D. sativa forma spontanea Makino 



NiGA-KASHU. A wild phase with bitter, nonedible bulbils 

 and tuberous roots. 



4. Dioscorea gracillima Miq. Tachidokoro. Rhi- 

 zomes long-creeping; stems elongate, branched; leaves ovate, 

 deltoid-ovate to elliptic, 5-10 cm. long, 2.5-7 cm. wide, 

 acuminate, deeply cordate, the margins somewhat uneven, 

 entire or shallowly lobed, glabrous; inflorescence spicate; 

 flowers sessile with spreading tepals, the staminate erect, often 

 branched, the pistillate loosely arranged; stigma 3-fid, entire; 



capsules depressed ovate-orbicular; seeds wing-margined. 



May-June. Honshu, Shikoku, Kyushu. 



5. Dioscorea asclepiadea Prain & Burkill. Tsukushi- 

 TACHiDOKORO. Plants glabrous; stems slightly elongate, green; 

 leaves thin, green, broadly deltoid-lanceolate to narrowly ovate- 

 deltoid, 8-15 cm. long, 4-7 cm. wide, deeply cordate, mucro- 



nate, entire or sometimes undulate, the basal margins imbri- 

 cate; staminate inflorescence branched, the flowers loose, 



yellow-green, short-pedicelled, the tepals spreading. Apr.- 



May. Kyushu. 



6. Dioscorea tokoro Makino. T). yo\usaii Prain & Bur- 

 kill Onidokoro, Tokoro. Plants glabrous; stems elon- 

 gate, branched; leaves thin, cordate or deltoid-cordate, 5-12 

 cm. long, 5-10 cm. wide, acuminate, entire; inflorescence some- 

 what elongate, erect, the staminate often branched; stami- 

 nate flowers yellowish green, short-pedicelled, the pistillate 

 pendulous; tepals minutely toothed on upper margin, flat, 

 spreading; capsules broadly obovate-elliptic, about 15 mm. 



long; seeds with a broad wing on one side. July-Aug. 



Thickets in lowlands to the foothills; Hokkaido, Honshu, Shi- 

 koku, Kyushu; common. 



7. Dioscorea nipponica Makino. Uchiwadokoro. 

 Stems elongate; leaves thin, long-petioled, broadly ovate to 

 ovate-cordate, 7-15 cm. long, 4-12 cm. wide, usually witla short 

 coarse hairs, palmately lobed or rarely entire, long-acuminate; 

 staminate inflorescence spicate, elongate, sometimes branched, 

 the flowers few, in fascicles, short-pedicelled, the pistillate usu- 

 ally simple, pendulous; capsules broadly obovate; seeds with a 



broad wing on one side. ^Aug. Hokkaido, Honshu (n. and 



centr. distr.). Korea and China. 



8. Dioscorea tenuipes Fr. & Sav. Himedokoro. Stems 

 elongate; leaves thin, deltoid-cordate, or sometimes lanceolate 

 with the basal margins prominendy auriculate, glabrous, 5-10 

 cm. long, 2.5-7 cm. wide, long-acuminate, sometimes with 

 minute papillae on the nerves beneath, entire, the petioles 

 usually with a small auriclelike appendage at base; inflores- 

 cence pendulous, the staminate flowers loose, slenderly pedi- 

 celled, the tepals entire, slightly recurved on margin; capsules 

 orbicular, somewhat angular; seeds wing-margined. July- 

 Aug. Honshu (Kanto Distr. and westw.), Shikoku, Kyushu. 



9. Dioscorea quinqueloba Thunb. Kaededokoro. 

 Plants elongate, branched, usually with short coarse hairs; 

 leaves relatively large, green, cordate, 6-12 cm. long, 4-10 cm. 

 wide, palmately 5- to 9-lobed, the median lobes narrowly ovate, 

 acuminate, the lateral lobes rounded to obtuse, smaller; stami- 

 nate inflorescence sometimes branching, the flowers short- 

 pedicelled, becoming reddish brown when dry; tepals spread- 

 ing, rather thick; capsules obovate-orbicular; seeds wing- 

 margined. July-Sept. Honshu (centr. distr. and westw.), 



Shikoku, Kyushu. Korea, China, and Ryukyus. 



10. Dioscorea septemloba Thunb. Kikubadokoro. 

 Plants glabrous; leaves becoming dark when dry, 5-12 cm. 

 long and as wide, usually cordate, usually palmately 5- to 7- 

 lobed, the median lobe deltoid-ovate to narrowly ovate, long- 

 acuminate, the lateral lobes deltoid, acuminate to rounded, the 

 petioles without a basal appendage; inflorescence pendulous. 



