rOLV(iONACEyK. (BUCKWHEAT FAMILY.) 439 



* * Annuals, low; valves bearing long awns or bristles. 



6. R. maritimus, L. (Golden Dock.) Minutely pubescent, diffusely 

 branched, 6-12' high; leaves lance-linear, wavy-margined, the lower auricleil 

 or heart-shaped at base ; whorls excessively crowded in leafy and compact or 

 interrupted spikes; valves rhombic-oblong, lance-pointed, each bearing 2-3 

 long awn-like bristles on each side, and a large grain on the back. — Sea-shore, 

 Mass. to N. C. ; also from 111. to Minn., and westward. 



§ 2. ACETOSA. (Sokrel.) Flowers dioecious, small, in a terminal naked 

 panicle; herbage sour; some leaves halberd -shaped ; smooth perennials, 

 spreading by running rootstocks, Jlowering in spring. 



7. R. hastatulus, Baldw. Stem simple, l - 2° high ; leaves nearly as in 

 the next; pedicels jointed at or below the middle; valves of the fruiting cabjx 

 round -heart-shaped , thin, finely reticulated, naked, mamj times larger than the 

 achene. (R. Engelmanni, Zerfei.) — S. W. 111. to E. Kan., Tex., and Fla. ; 

 Kiverhead, Long Island {Young). 



R. AcETOSELLA, L. (FiELD or Sheep Sorrel.) Low (6-12' high); 

 leaves narrow-lanceolate or linear, halberd-form, at least those of the root, the 

 narrow lobes entire; pedicels jointed with the flower ; valves scarcelj enlarging 

 in fruit, ovate, naked. — Abundant everywhere. (Nat. from Eu.) 



R. Acet6sa, L. (Sorrel Dock.)' Like the last, but /«//er (1 -.3° high); 

 leaves oblong or broadly lanceolate ; valves eyitarging in fruit and orbicular, 

 the outer rejiexed. — Charlotte, Vt., and Penn Yan, N. Y. (Xat. from Eu.) 



4. POLYGONUM, Tourn. Knotweed. 



Calyx mostly 5-parted ; the divisions often petal-like, all erect in fruit, with- 

 ering or persistent. Stamens 4-9. Styles or stigmas 2 or 3 ; achene accord- 

 ingly lenticular or 3-angular. Embryo placed in a groove on the outside of 

 the albumen and curved half-way around it ; the radicle and usually the co- 

 tyledons slender. — Pedicels jointed. Ours all herbaceous, with filjrous roots 

 (except n. 19), flowering through late summer and early autunm. (Name 

 composed of ttoXvs, man//, and yow, knee, from the numerous joints.) 



§ 1. POLYGONUM proper. Floivers in axillary fascicles or spicate ivith 

 foliaceous by-acts; leaves and bracts jointed upon a very short petiole adnate 

 to the short sheath of the 2-lobed or lacerate scarious stipules : stems striate ; 

 calyx 5 - 6-parted, usually more or less herbaceous ; stamens 3-8, the 3 inner 

 filaments broad at base; styles 3; cotyledons incumbent; albumen horny; 

 glabrous annuals^ except n. 1. (§ Avicularia, Meisn.) 

 * Leafy throughout. 



1 . P. maritimTim, L. Perennial, at length woody at base (or sometimes 

 annual), prostrate, glaucous, the stout stems very shortly jointed; leaves thick, 

 oval to linear-oblong (3-10" long), exceeding the nodes; stipules very con- 

 spicuous; sepals petaloid; stamens 8; achene smooth and shining, exserted. — 

 Sea-coast from Mass. to Ga. (Eu.) 



2. P. aviculare, L. Slender, mostly prostrate or ascending, bluish-green ; 

 leaves oblong to lanceolate (3-10" long), usually acute or acutish ; sepals 

 hardly 1" long, green with pinkish mnrgins ; stamens 8 (rarely 5) ; achene dull 

 and minutely granular, mostly included. — Common everywhere in yards, 

 waste places, etc. (Eu., Asia.) 



