410 



POLYGONACEAE 



leaflike bract at base, the peduncles short, often with stipitate 

 glands on the upper parts; flowers white, 2.5-3 mm. long; 

 achenes black, biconvex, orbicular, about 1.5 mm. across, im- 



pressed-punctulate, dull. Aug.-Oct. Damp woods in 



mountains; Hokkaido, Honshu, Shikoku, Kyushu; common. 

 ^Korea, China, Formosa, and India. 



23. Polygonum chinense L. P. chinense var. thunber- 

 gii Meissn.; Rumex umhellatus Houtt.; Persicaria umbellata 



(Houtt.) Nakai Tsuru-soba. Perennial herb; stems 



elongate, much branched, glabrous, sometimes scandent; 

 leaves broadly ovate to oblong-ovate, 4-10 cm. long, 3-6 cm. 

 wide, glabrous or with few ratlier fleshy hairs on nerves be- 

 neath, abruptly acuminate to acute, truncate at base, the peti- 

 oles short, the sheaths membranous, obliquely truncate, nerved, 

 1-1.5 cm. long; inflorescence globose, an erect terminal panicle, 

 densely 10- to 20-flowered, 6-10 mm. across, the peduncles 

 often with scattered fleshy hairs; flowers white, the perianth- 

 segments about 3 mm. long, slightly accrescent, to 4 mm. long 

 after flowering, slighdy fleshy; achenes glabrous, black, tri- 

 gonous, ovoid-globose, about 2.5 mm. long, dull. Thickets 



and hedges in lowlands and hills; Honshu (Izu Isls., Kii Prov. 

 and Chugoku Distr.), Shikoku, Kyushu; common southw. 

 China, Ryukyus, and Formosa. 



24. Polygonum orientale L. P. orientale var. pilosum 

 (Roxb.) Meissn.; P. pilosum Roxb.; Amblygonum pilosum 



(Roxb.) Nakai O-ke-tade. Prominently spreading-pilose 



annual; stems rather stout, erect, much branched, 1-1.5 m. 

 long; leaves broadly ovate to ovate-cordate, 10-20 cm. long, 

 7-15 cm. wide, short-acuminate, cordate or the upper ones 

 subrounded at base, long-petiolate, die sheaths tubular, mem- 

 branous, pilose, 7-30 mm. long, somewhat wing-margined; 

 inflorescence branched, the flower spikes rather dense, pedun- 

 cled, nodding to pendulous, 5-12 cm. long; flowers red to 

 pink, 3-4 mm. long; achenes orbicular, about 3 mm. long, 



dull, compressed. Cultivated and often naturalized. 



China, India, and Malaysia. 



25. Polygonum viscosum Hamilt. Persicaria viscosa 



(Hamilt.) Gross Nioi-tade. Annual; stems erect, 



branched above, 40-120 cm. long, coarsely long-hairy and 

 short stipitate-glandular; leaves short-petiolate, lanceolate to 

 deltoid-lanceolate, gradually acuminate, cuneate to rather ab- 

 rupdy narrowed at base, 7-15 cm. long, 1.5-4 cm. wide, often 

 with sessile discoid glands on the upper side or on both sides, 

 the sheaths tubular, pilose, 7-15 mm. long; spikes 3-5 cm. 

 long, densely many-flowered, the peduncles and bracts long- 

 hairy and short-stipitate glandular; flowers reddish, 2.5-3 mm. 

 long; achenes black-brown, trigonous, 2.5-3 mm. long, broadly 



ovoid. Aug.-Oct. Honshu, Shikoku, Kyushu. ^Korea, 



China, and India. 



26. Polygonum amphibium L. Persicaria amphibia 

 (L.) S. F. Gray; Persicaria amurensis (Korsh.) Nieuwl.; 

 Polygonum amphibium var. amurense Korsh. and var. vesti- 



tum Hemsl. Ezo-no-mizu-tade. Perennial herb with 



creeping rhizomes; stems elongate, glabrous, slightly branched 

 in the floating form, short and ascending in the terrestrial 

 form; floating leaves oblong, 5-15 cm. long, 2-6 cm. wide, gla- 

 brous, lustrous above, red-brown when dried, obtuse to 

 rounded with a mucro at apex, shallowly cordate at base, the 

 lateral nerves rather numerous, spreading, the petioles rather 

 long, the sheaths membranous, glabrous; spikes axillary, 2-4 

 cm. long, pedunculate, often branched below, cylindric, erect, 

 densely many-flowered; flowers reddish, 3-4 mm. long, the 



pedicels longer than the bracts; achenes black-brown, biconvex, 

 suborbicular, about 2.5 mm. long, slighdy lustrous. June- 

 Sept. Ponds and shallow lakes; Hokkaido, Honshu (Mutsu 

 and Ugo Prov.). Temperate regions of the N. Hemisphere. 



27. Polygonum lapathifolium L. P. nodosum Pers.; 

 Persicaria nodosa (Pers.) Opiz; Polygonum tenuiflorum Presl; 



P. \omarovii Lev. O-inu-tade. Annual; stems rather 



stout, much-branched, erect, glabrous, 50-120 cm. long, red- 

 dish, the nodes swollen; leaves lanceolate, 7-20 cm. long, 1.5-5 

 cm. wide, acuminate, acute at base, often red-brown when 

 dried, with minute strigose hairs on both sides especially on 

 nerves and on margin, the lateral nerves 20 to 30 pairs, the 

 petioles short; sheath tubular, slenderly nerved, glabrous or 

 rarely short-cilia te, 1-2 cm. long; spikes many, cylindric, nod- 

 ding or pendulous, densely many-flowered, 4-10 cm. long; 

 flowers about 2.5 mm. long, white or reddish, the perianth- 

 segments 4, the lateral nerves of the 2 outer segments distinct, 

 dichotomously forked in 2 recurved branches; achenes flat, 



suborbicular, lustrous, deep brown, 1.5-2 mm. across. 



June-Nov. Sunny grassy places and waste grounds in low- 

 lands; Hokkaido, Honshu, Shikoku, Kyushu; very common. 

 Temperate regions of the N. Hemisphere. 



28. Polygonum scabrum Moench. P. lapathifolium L. 

 pro parte; P. tomentosum Schrank, non Willd.; P. incanum 



F. W. Schmidt Sanae-tade. Closely resembling No. 27, 



but smaller; stems 20-60 cm. long, slightly branched; leaves 

 narrowly lanceolate to narrowly ovate, 5-12 cm. long, 0.8-3.5 

 cm. wide, obtuse to subacute, scabrous, also appressed pilosu- 

 lous on midrib on both sides and on margin, the lateral nerves 

 7 to 15 pairs, ascending, arcuate, the petioles short; sheaths 

 membranous, tubular, 7-15 mm. long; spikes ellipsoidal to 

 short-cylindric, 1-4 cm. long, erect, densely many-flowered; 

 flowers white or reddish, about 3 mm. long, the perianth- 

 segments nearly as long as the achenes; achenes flat, orbicular, 



lustrous, dark brown, 2-3 mm. across. May-Oct. Grassy 



sunny places and waste grounds in lowlands; Hokkaido, Hon- 

 shu, Shikoku, Kyushu; common. Temperate and warmer 



regions of the N. Hemisphere. 



29. Polygonum japonicum Meissn. Persicaria japonica 

 (Meissn.) Gross Shirobana-sakura-tade. Dioecious per- 

 ennial herb with long creeping rhizomes; stems erect, 60-100 

 cm. long, sparingly branched, glabrescent to slighdy appressed- 

 pilose; leaves rather thick and firm, lanceolate, 7-12 cm. long, 

 1-2 cm. wide, acuminate at both ends, strigose above especially 

 toward the margin and on the nerves beneath, the lateral 

 nerves 15 to 25 pairs, die petioles very short; sheaths tubular, 

 nerved, truncate at apex, membranous, with rather firm 

 bristly cilia 8-15 mm. long; spikes terminal, few to several, 

 linear or narrowly cylindric, 7-12 cm. long, nodding, loosely 

 to rather densely many-flowered, the pedicels distinct, the 

 perianth white, sometimes greenish below in fruit, 3-4 mm. 

 long; stamens shorter than the style in pistillate flowers; 

 styles 2 or 3; achenes lenticular or compressed-trigonous, 



lustrous, elliptic-ovate, 2-2.5 mm. long. Aug.-Oct. Wet 



grassy places in lowlands; Hokkaido, Honshu, Shikoku, Kyu- 

 shu; rather common. s. Korea, Ryukyus, and China. 



30. Polygonum conspicuum (Nakai) Nakai. P. japoni- 

 cum var. conspicuum Nakai; Persicaria conspicua (Nakai) Na- 

 kai; Polygonum sterile Nakai; Persicaria sterilis (Nakai) Na- 

 kai Sakura-tade. Closely resembles the preceding; stems 



less branched; spikes solitary to few; flowers larger, more 

 loosely arranged, reddish, the perianth-segments 4-6 mm. long. 



