408 



POLYGONACEAE 



solitary, 2-5 cm. long, cylindric, densely flowered, with bulbils 

 on lower portion; flowers rose, about 3 mm. long, with slightly 



exserted stamens. July-Oct. Alpine slopes; Hokkaido, 



Honshu (centr. and n. distr.). Arctic and alpine regions of 



the N. Hemisphere. 



7. Polygonum hayachinense Makino. Bistorta haya- 



chinensis (Makino) Gross Nambu-tora-no-o. Glabrous 



perennial; stems erect, 10-30 cm. long, sparsely leafy, the 

 sheaths to 3.5 cm. long; radical leaves rather firm, ovate to 

 narrowly so, 3.8 cm. long, 15-35 mm. wide, obtuse to sub- 

 acute, shallowly cordate to rounded at base, not decurrent to 

 the petiole, rather lustrous above, often glaucous beneath; 

 spikes solitary and terminal, ellipsoidal, densely flowered, 15- 

 30 mm. long; perianth about 3.5 mm. long, about as long as 



the pedicel; stamens slightly exserted. Aug. Alpine slopes; 



Honshu (Mount Hayachine in Rikuchu) ; very rare. 



8. Polygonum bistorta L. Bistorta vulgaris Hill; B. 



major S. F. Gray Ibuki-tora-no-o. Glabrous perennial, 



sometimes white-pilose on the leaves underneath; rhizomes 

 thick; stems 30-80 cm. long; radical leaves long-petioled, 

 lanceolate to broadly so, 8-20 cm. long, 2-5 cm. wide, acumi- 

 nate, the tip obtuse, truncate and broadly decurrent to the 

 petiole, with rather prominent veinlets, deep green above, 

 paler to glaucous beneath; the lower cauline leaves similar to 

 the radical, but smaller, the upper ones cordate, with longer 

 sheaths; spikes densely many-flowered, cylindric, 3-6 cm. long, 

 the perianth pale pink or white, about 3 mm. long, the pedi- 

 cels relatively long; stamens exserted; achenes about 3 mm. 

 long, trigonous, lustrous. July-Sept. Grassy slopes in high- 

 lands and subalpine regions; Hokkaido, Honshu, Shikoku, 



Kyushu; rather common. High mountains and temperate 



regions of the Old World. 



9. Polygonum su£Fultum Maxim. Bistorta suffulta 



(Maxim.) Greene Kurin-yuki-fude. Perennial, glabrous 



or white-pilose on underside of leaves; rhizomes thickened, 

 stems 20-40 cm. long; radical leaves membranous, long- 

 petioled, broadly ovate, 5-10 cm. long, 3-7 cm. wide, abruptly 

 acute to abruptly acuminate, cordate, glaucous beneath; cau- 

 line leaves 3-5, ovate-cordate, sessile and clasping, rather small, 

 short-spicate from the axils; terminal spikes cylindric, 1-3 cm. 

 long, rather densely flowered; perianth 2.5-3 mm. long, white; 



stamens exserted; achenes lustrous, slightly exserted. 



Mountains; Honshu, Shikoku, Kyushu. Korea and China. 



10. Polygonum perfoliatum L. Persicaria perjoliata 



(L.) Gross IsHiMi-KAWA. Scandent glabrous annual; 



stems much elongate, branched, 1-2 m. long, retrorsely 

 prickly; leaves deltoid, thinly membranous, retrorsely prickly 

 on the nerves beneath, glaucous or pale green, 3-6 cm long 

 and as wide, acute to subacute, truncate to shallowly cordate, 

 the margins sometimes minutely retrorsely scabrous, the peti- 

 oles long, retrorsely prickly; sheaths scarcely tubular, the 

 dilated leaf like limb orbicular, perfoliate, green; spikes short, 

 1-2 cm. long, subtended by an orbicular leaflike bract, the 

 pedicels short; perianth 3-4 mm. long, pale greenish white, the 

 segments broadly elliptic, becoming fleshy and blue in fruit; 

 achenes inflated, obsoletely trigonous, black, lustrous, about 



3 mm. long and as wide. July-Oct. Wet thickets and 



along rivers in lowlands; Hokkaido, Honshu, Kyushu; com- 

 mon. Korea, China, Malay Peninsula, and India. 



11. Polygonum senticosum (Meissn.) Fr. & Sav. 

 Truellum japonicum Houtt.; Chylocalyx senticosus Meissn.; 

 Persicaria senticosa (Meissn.) Gross Mamako-no-shiri-nu- 



Gui. Slender, puberulent, much-branched, scandent annual; 

 stems 1-2 m. long, scabrous; leaves deltoid, 4-8 cm. long and 

 as wide, acuminate, obtuse or subobtuse at the tip, broadly 

 cordate, green, puberulous on both sides, the petioles re- 

 trorsely prickly; sheaths very short, membranous, the marginal 

 limb clasping, reniform or subcordate; inflorescence somewhat 

 capitate, densely several-flowered, reddish, long-peduncled, the 

 pedicels very short, the perianth 3.5-4 mm. long, the segments 

 elliptic; achenes ovoid-globose, inflated, obsoletely trigonous, 



dull, black, about 3 mm. long and as wide. June-Sept. 



Thickets in lowlands and foothills; Hokkaido, Honshu, Shi- 

 koku, Kyushu; common. Korea and China. 



12. Polygonum debile Meissn. P. debile var. triang- 

 ulare Meissn.; Persicaria debilis (Meissn.) Gross; Persicaria 



triangularis (Meissn.) Nakai Miyama-tani-soba. Soft 



glabrescent annual; stems ascending to erect, decumbent at 

 base, branched, 10-30 cm. long, the nodes sometimes with soft 

 very short retrorse prickles on the nodes, glabrous or puber- 

 ulous; leaves cauline, deltoid, 2-4 cm. long and as wide, 

 petiolate, the upper subsessile, thin, green, scattered coarsely 

 pilose above and on the nerves beneath, short-ciliolate, acumi- 

 nate with an obtuse tip, truncate at base, the petioles not 

 prickly; sheaths short, with a small dilated limb; inflorescence 

 spicate or subcapitate, terminal and axillary, often forked, 

 short-peduncled; flowers few, white, about 3 mm. long, the 

 perianth-segments elliptic; achenes ovoid, trigonous, lustrous, 



brown, about 3 mm. long. July-Oct. Damp woods in 



mountains; Honshu, Shikoku, Kyushu; rather common. 



13. Polygonum maackianum Regel. P. thunbergii var. 

 tnaac\ianum (Regel) Maxim.; Persicaria maac\iana (Regel) 



Nakai Sade-kusa. Scandent or straggling annual, the 



entire plant minutely stellate-pubescent; stems ascending or 

 sometimes suberect, decumbent at the base, branched, 40-100 

 cm. long, retrorsely prickly; leaves divided, petiolate, hastate, 

 4-7 cm. long, 3-7 cm. wide, cordate, the median lobe narrowly 

 ovate, acuminate to acute, obtuse at tip, the lateral lobes similar 

 but small, rather deflexed, the petioles and the nerves on un- 

 derside of leaves retrorsely prickly; sheaths short, the orbicular 

 green limb 5-15 mm. across; inflorescence pedunculate, few- 

 flowered, cymose, die peduncles usually with stipitate glands, 

 the pedicels very short; flowers reddish, 4-5 mm. long, the 

 perianth-segments elliptic; achenes ovoid, trigonous, about 3.5 



mm. long, lustrous, dark brown. Aug.-Oct. Wet places 



along ditches, riverbanks, and paddy fields on lowlands; Hon- 

 shu, Shikoku, Kyushu; rather common. Korea, China and 



Ussuri. 



14. Polygonum thunbergii Sieb. & Zucc. P. debile var. 

 hastatum Meissn.; P. hastatotrilobum Meissn.; P. stoloniferum 

 F. Schmidt; Persicaria thunbergii (Sieb. & Zucc.) Gross; 



Persicaria stellatotomentosa Nakai ^Mizo-soba. Glabrous 



or pilose, very rarely stellate-pilose annual; stems elongate, 

 erect from the decumbent base, 30-100 cm. long, retrorsely 

 prickly, glabrous; leaves petiolate, the upper ones sessile, re- 

 trorsely prickly on the nerves beneath, hastate, coarsely pilose 

 on both sides, 4-10 cm. long, 3-7 cm. wide, truncate to shal- 

 lowly cordate, the midlobe ovate to broadly so, acuminate, 

 subobtuse at the tip, the lateral (basal) lobes smaller, acute to 

 obtuse, the petioles often narrowly winged, usually retrorse- 

 prickly; sheaths 5-8 mm. long, obliquely truncate at apex, 

 membranous, short-ciliate, rarely with a minute limb; inflores- 

 cence cymose, 10- to 20-flowered, the peduncles short-pubes- 

 cent and stipitate-glandular, the pedicels very short; flowers 



