POLYGONUM POLYGONAOEiE 585 



RUMEI 



leaves : calyx nearly a line long, sessile, 5-cleft. In moist places, eastern 

 Washington to southern Oregon and California. 



Subgenus vi Tiniaeia Meisn. Monog. 62.^ Annual or peren- 

 nial more or less twining plants with usually cordate or truncate 

 leaves. Ocreae membranaceous, funnelform, oblique, naked at 

 the summit. Flowers in axillary or terminal clusters or racemes. 

 Calyx 5-parted, the outer segments keeled or winged. Stamens 8. 

 Style 3-parted or wanting. Achenes triquetrous. .Cotyledons 

 accumbent. 



P. CONVOLVULUS L. Sp. 364. Annual : Glabrous : stem slender prostrate 

 or twining, 1-4 leet long, branched : leaves broadly to narrowly ovate or ov- 

 ate-sagittate, 1-3 inches long, acuminate, somewhat undulate and crisped, 

 on slender petioles : flowers in small axillary clusters and terminal racemes 

 on slender reflexed pedicels : calyx green or whitish, about 2 lines long, the 

 segments oblong, obtuse, closely investing the triquetrous achene. Com- 

 mon in cultivated fields and gardens. Naturalized from Europe. 



P. DUMETOBUM L. Sp. ed. 2, 522. Perennial : bright green and glabrous 

 throughout : stems weak and slender, extensively twining 2-20 feet long : 

 leaves ovate-cordate, 1-4 inches long, acuminate, petioled or nearly sessile; 

 flowers in axillary racemes 2 inches long: calyx yellowish-green, drooping, 

 nearly 3 lines long. Said to grow in our region but I. > have not seen it. 

 Missouri to Tennessee and Europe. 



6 EUMEX L. Sp. 333. 



Coarse perennial, biennial or annual herbs, some tropical spe- 

 cies shrubs or trees, with more or less acid juice, alternate leaves 

 with sheathing stipules and small flowers fascicled or verticillate 

 in paniculate racemes. Flowers perfect, polygamous or dioecious, 

 on jointed pedicels. Calyx S-parted or of 6 distinct sepals 

 the outer 3 herbaceous, spreading or reflexed, the inner larger 

 and more or less colored, usually becoming enlarge^and'reticulat- 

 ed in fruit, appressed to the 3-angled achene. Stamens 6: filaments 

 very short. Style 3-.parted,. with peltate tufted stigma. Embryo 

 curved or nearly straight, borne in one of the faces of the achene. 



§ 1 AcETOSELLA Trclcase Rev. Rum. 76, Dioecious perenni- 

 als with acid juice. Outer segments of the calyx without dorsal 

 callosities, not reticulated nor larger than the achene. 



-R, ACETOSELLA L. Sp. 338. ( SoREEL. ) Glabrous throughout stems 

 slender, 6-12 inches high, tufted, propagating by creeping rootstocks : leaves 

 oblanceolate, acute, the lower mostly hastate with a large decurrent, rarely 

 toothed auricle on each side, petioled, 2-5 inches long, the upper gradually 

 I'ediiced and entires panicle more or less compound, usually reddish, the 

 filiform ascending branches, leafless: pedicels capillary, articulated at 

 the summit : flowers about a line long. Common in fields and waste pi a- 

 ces throughout most of North America and Europe. 



§ 2 AcETOSA Campd. Monog. Rumex, Dioecious perennialsg 

 the leaves with acid juice. Inflorescence with slender leafles 

 branches. Injier segments of the calyx rather finely reticulated 

 becoming round-cordate and much^larger than the achene. 



R. pancifolius Nutt. Mss. Watson Bot. King, 314. Stems somewha 



