POLYGONACEAE 403 



sepals sometimes connate at base, imbricate in bud (petals absent), sometimes accrescent after anthesis; stamens 6-9, rarely many, 

 inserted at the base of pcriandi-segments; ovary superior, trigonous or lendcular, I-locular, 1-ovuled; styles 2 or 3, often connate 

 at base; fruit an achene, indehiscent, enclosed in the persistent perianth, the pericarp hard, the testa membranous; endosperm 

 copious, mealy, the embryo often curved. About 30 genera, with about 800 species, cosmopolitan. 



lA. Stigma fimbriate; inner perianth-segments usually accrescent after anthesis. 



2A. Perianth-segments (sepals) 6; styles 3; achenes trigonous 1. Rumex 



2B. Perianth-segments (sepals) 4; styles 2; achenes lenticular 2. Oxyria 



IB. Stigma capitellate or 2-lobed, rarely fimbriate but the inner perianth-segments unchanged after anthesis 3. Polygonum 



1. RUMEX L. GisHi-GisHi Zoku 



Perennial or annual herbs, rarely subshrubs; leaves radical and cauline, alternate, the stipules sheathed; flowers bisexual or 

 unisexual, small, fascicled at the nodes, ultimately disposed in terminal racemes or panicles; perianth-segments biseriate, 6, rarely 

 4, nearly equal, herbaceous or coriaceous, entire or dentate to spine-margined, the midrib sometimes swollen at the middle, the 

 outer 3 unchanged in fruit, the inner 3 usually accrescent after anthesis; stamens 6; styles 3, the stigma laciniate-fimbriate; 

 achenes trigonous, enclosed in the accrescent inner perianth-segments; embryo lateral. Many species, cosmopolitan. 



lA. Leaves hastate, with acute auricles on each side; flowers usually unisexual (plants dioecious) ; styles lateral. 



2 A. Perianth-segments not accrescent in fruit \. R. acctosdla 



2B. Perianth-segments of the inner whorl accrescent and winglike in fruit. 



3A. Leaves broadly lanceolate or oblong; sheath dentate or lobed from the earlier stage 2. R. acetosa 



3B. Leaves narrowly ovate to broadly so; sheath entire while young 3. R. montanus 



IB. Leaves cuneate, rounded or cordate at base, without auricles on lower margin; flowers bisexual; styles terminal; inner perianth- 

 segments accrescent. 

 ■lA. Inner perianth-segments orbicular to orbicular-cordate in fruit, the midrib not thickened or only slighdy swollen in one sepal. 

 5A. Verticils or fascicles of fruit dense; leaves glabrous, the lower oblong or narrowly so, the upper linear-oblong. 



6A. Leaves cordate; inner perianth-segments truncate to rounded at base 4. i?. aquaticus 



6B. Leaves narrowed to truncate or rounded at base; irmer perianth-segments cordate 5. /?. longifoliiis 



5B. Verticils or fascicles of fruit interrupted; leaves with hairlike papillae especially on nerves beneath. 

 7A. Lower leaves ovate or broadly so. 



8A. Inner perianth-segments shallowly toothed in fruit 6. R. madaio 



8B. Inner perianth-segments with hooked spines on margin in fruit 7. R. nepaUnsis 



7B. Lower leaves deltoid-cordate; inner perianth-segments entire 8. R. gmelinii 



4B. Inner perianth-segments with a prominent tubercle at the center. 



9A. Inner perianth-segments orbicular to orbicular-cordate, 4-7 mm. wide, acutely toothed to nearly entire. 



lOA. Radical leaves cordate; inner perianth-segments orbicular-cordate or ovate-cordate, more or less distinctly toothed. 



9. R. japonicus 

 lOB. Radical leaves rounded to truncate or cuneate at base; inner perianth-segments ovate-orbicular, entire or nearly so. 



10. R. crispus 

 9B. Inner perianth-segments ovate or narowly so. 



IIA. Inner perianth-segments entire, about 1.5 mm. wide; stems usually dark purplish; leaves often partially blood-purple variegated. 



11. i?. conglomeratus 

 I IB. Inner perianth-segments prominendy toothed or spined on margin. 



12A. Inner perianth-segments 2.5-3 mm. long, narrower than the spines on margin; verticils of flowers many-flowered, often 



globose 12. i?. maritimus 



12B. Inner perianth-segments 4-6 mm. long, broader than the length of marginal teeth or spines; verticils of flowers few- to rather 

 many-flowered. 

 13A. Lower leaves oblong-ovate or broadly ovate, cordate, with hairlikc papillae beneath; verticils of flowers rather contiguous 



above, separated in the lower ones 13. R. obtusifolius 



13B. Lower leaves oblong-lanceolate, smooth, rounded at base; verticils of flowers rather widely separated. . . 14. R. nipponicus 



1. Rumex acetosella L. Hi\rE-suiBA. Dioecious per- on the inflorescence; rhizomes short, with thick adventitious 

 ennial herb, acid to taste, from slender creeping branched rhi- roots; stems erect, 30-80 cm. long, usually simple, few-leaved; 

 zomes, glabrous or with scattered hairlike papillae; stems slen- radical leaves petioled, broadly lanceolate to oblong, hastate, 

 der, erect, few-leaved, sometimes branching; radical leaves 5-10 cm. long; panicles terminal, erect, 10-30 cm. long, nar- 

 long-petioled, hastate, 3-6 cm. long, 1-2 cm. wide, acute to row, the branches erect, slender; staminate flowers with the 

 obtuse, the cauline rather small, the sheaths scarious; in- sepals all alike, 2.5-3 mm. long, tlie outer sepals of the pistillate 

 florescence paniculate, the flowers small, about 2 mm. long, the flowers elliptic, reflexed, to 1 mm. long, the inner ones 

 sepals unchanged in fruit, not warty; achenes broadly elliptic, strongly accrescent, often pinkish, orbicular-cordate, mem- 

 trigonous, brown, slighdy lustrous, about 1.2 mm. long, the branous, net-veined, about 5 mm. long and as wide; achenes 



angles rather obtuse. May-July. Waste grounds and elliptic, black-brown, lustrous, trigonous, about 2 mm. long, 



meadows in lowlands and foothills; Hokkaido, Honshu, Shi- the angles acute. May-June. Meadows; Hokkaido, Hon- 



koku, Kyushu; naturahzed and very common locally. shu, Shikoku, Kyushu; very common. Temperate regions 



Europe and w. Asia. of the N. Hemisphere. 



2. Rumex acetosa L. Suib.\. Dioecious perennial 3. Rumex montanus Desf. R. arifolius All., non L. f. 

 herb, acid tasting, glabrous or with obsolete granular papillae Takane-suiba. Closely resembles the preceding; radi- 



