POLYGONACEAE 



407 



39B. Leaves thinly membranous, green or pale green, without sessile discoid glands beneath. 



42A. Spikes densely flowered, erect; achenes trigonous 40. P. erectominiis 



42B. Spikes loosely flowered, nodding above; achenes trigonous or lenticular 41. P. taqtietii 



23B. Perennials with rhizomes; inflorescence a densely flowered panicle; achenes rather large, often exsertcd from the perianth, 

 the pericarp membranous or chartaceous. 

 43A. Plants less than 50 cm. high; achenes included or only slightly exserted from the perianth; leaves subsessile or very 

 short-pctioled. 



44A. Leaves lanceolate to broadly so, gradually narrowed below, not rounded at base 42. P. ajanense 



44B. Leaves ovate to broadly so, rounded to very broadly cuneate at base 43. P. nakflii 



43B. Plants 40-100 cm. high; achenes 3-4 times as long as the perianth; lower leaves distinctly petioled. . . 44. P. weyrichii 

 223. Stems scandent, or if not the outer perianth-segments winged on back. 

 45A. Plants bisexual; flowers in loose spikes or axillary fascicles. 



46.\. Perianth-segments not winged 45. P. convolvulus 



46B. Outer perianth-segments winged on the back in fruit. 



47A. Fruit inclusive of perianth obovate, about 10 mm. long, prominently decurrent to the pedicel. . . 46. P. dentatoalatum 

 47B. Fruit inclusive of perianth elliptic or nearly orbicular, 5-7 mm. long, only slightly decurrent on the pedicel. 



47. P. dumetorum 

 45B. Plants dioecious; flowers in dense much branched panicles. 



48A. Stems scandent 48. P. mullifiorum 



48B. Stems erect, ascending above. 



49A. Leaves 6-12(-15) cm. long, scarcely glaucous, often papillose-pilose to papillose-scabrous beneath; stems 50-150 cm. 



long 49. P. cuspidatum 



49B. Leaves usually 20-30 cm. long, glaucous, glabrous beneath; stems about 2.5 m. long 50. P. sachalinense 



1. Polygonum filiforme Thunb. P. virginianum var. pU- mm. long, 2-8 mm. wide, sometimes slightly glaucous, rather 

 jorme (Thunb.) Merr.; Tovara filiformis (Thunb.) Nakai; T. thick, subacute, slightly narrowed toward the base, subsessile, 

 virginiana var. filiformis (Thunb.) Steward; Sunania filiformis the upper leaves often much smaller and deciduous, the in- 



(Thunb.) Rafin. Mizu-hiki. Coarsely appressed-strigose florescence then loosely spicate; sheaths 5-10 rrun. long, rather 



perennial herb from short, rather thick rhizomes; stems 40-80 many-nerved, laciniate; perianth-segments about 3 mm. long; 



cm. long; leaves elliptic to oblong, rarely obovate or ovate, achenes trigonous, exserted above, puncmlate, dull. Sept.- 



7-15 cm. long, 4-9 cm. wide, abrupdy acute with an obtuse dp, Oct. Sand dunes near seashores; Hokkaido, Honshu, Shi- 

 acute at the base, the petiole 5-30 mm. long; stipules 5-10 koku, Kyushu. 



mm. long, short-ciliate; spikes few, elongate, 20-40 cm. long, 4. Polygonum aviculare L. P. heterophyllum Lindm. 



loosely flowered, narrow; flowers short-pedicelled, rose-pink, Michi-yanagi. Glabrous annual; stems much-branched, 



rarely white, the perianth to 3 mm. long in fruit; achenes in- prostrate to ascending, rarely suberect, 10-40 cm. long, slen- 



flated-biconvcx, brown, elliptic, lustrous, about 2.5 mm. long; derly striate; leaves narrowly oblong to linear-lanceolate, 1.5-4 



styles 2, free, persistent, hooked at apex. Aug.-Oct. Woods cm. long, 3-12 mm. wide, membranous, usually green when 



and thickets in lowlands and hills; Hokkaido, Honshu, Shi- dry, obtuse; sheaths laciniate, 5-10 mm. long, weakly nerved; 



koku, Kyushu; common; variable. perianth 2.5-3 mm. long, green, red at the apex; achenes 



Var. neofiliforme (Nakai) Ohwi. P. neofiliforme Nakai; trigonous, scarcely exserted or included, punctulate, dull. 



Tovara neofiliformis (Nakai) Nakai; Sunania neofilijormis May-Oct. Meadows and riverbanks in lowlands; Hokkaido, 



(Nakai) Hara Shin-mizu-hiki. Plant thinly pilose with Honshu, Shikoku, Kyushu; very common and variable. 



shorter hairs; leaves usually short-acuminate. Honshu; Temperate regions of the N. Hemisphere. 



common. 5. Polygonum tenuicaule Biss. & Moore. Bistorta 



Var. smaragdinum (Nakai) Ohwi. Tovara smaragdina tenuicaulis (Biss. & Moore) Nakai Haru-tora-no-o. Gla- 



Nakai ex F. Maekawa; Sunania filiformis forma smaragdina brous, frequendy stoloniferous perennial with short thick rhi- 



(Nakai) Hara Nagaba-mku-hiki. Leaves narrower, zomes; radical leaves few, long-petioled, oblong-ovate, 3-8 cm. 



ovate-oblong to broadly lanceolate; flowers and fruit slightly long, 2-3 cm. wide, acuminate to acute, truncate to sub- 

 smaller. Honshu (Izu). rounded or shallowly cordate and abruptly decurrent to the 



2. Polygonum plebeium R. Br. Yambaru-michi-yanagi. petiole, membranous, sometimes slightly whitish beneath; 

 Glabrous herb; stems procumbent, often rooting at the nodes, scapes erect, 7-15 cm. long, 1- or 2-leaved or leafless; cauline 

 the branches with short internodes; leaves linear-oblong to leaves short-petioled or sessile, ovate or broadly so, sometimes 

 lanceolate, 8-15(-20) mm. long, 1.5-3.5 mm. wide, rather ovate-cordate; sheaths brown, scarious; spike 2-3.5 cm. long, 

 thick, obtuse, subsessile, the sheaths hyaline, scarious, 2-2.5 rather densely flowered, cylindric; perianth about 3 mm. long, 

 mm. long, nearly nerveless, laciniate; periandi-segments about white, slightly shorter than the stamens, as long as the pedicel; 

 2 mm. long; achenes trigonous, rhombic-ovoid, smooth, lus- achenes slighdy exserted, trigonous, lustrous; styles slender, 

 trous, dark brown, not exserted from the perianth. Re- Apr.-June. Honshu, Shikoku, Kyushu. 



ported to occur in Kyushu (Yakushima). Ryukyus, For- 6. Polygonum viviparum L. Mukago-tora-no-o. Usu- 



mosa, s. China, and Malaysia to Australia. ally glabrous erect perennial from short thick rather large 



3. Polygonum polyneuron Fr. & Sav. P. gymnolepis rhizomes; stems 10-30 cm. long, with few leaves; radical leaves 



Fr. & Sav.; P. propinquum sensu auct. Japon., non Ledeb. ratlier thick, long-petioled, linear-lanceolate to oblong-ovate, 



Aki-no-michi-yanagi, Ham-vmichi-yanagi. Glabrous annual; 2-10 cm. long, 8-25 mm. wide, subacute to obtuse, shallowly 



stems prominendy striate, suberect, much-branched, with the cordate to abruptly cuneate at base, slighdy lustrous above and 



branches rather thick; leaves oblanceolate to broadly so, 5-30 deep green, with fine veinlets, often glaucous beneath; spikes 



