238 POLYGONACEAE 



raceme ovoid, less than 2 cm. long; perianth mostly white; achenes smooth and 

 shining. Polygonum Bistorla limarifolium S. Wats. B. jejuna Greene. Alpine 

 swamps: Mont.— Colo. — Utah — Nev. Alp, — Mont, Je-Au. 



3. B. vivipara (L.) S. F. Gray. Blades of the basal leaves oblong or lance- 

 olate, 2-10 cm. long, 1-2.5 cm. wide; stem-leaves lanceolate to linear; raceme 

 narrowly cylindric, 2-10 cm. long, 0.5-1 cm. thick; perianth pale rose-colored 

 or white; achenes dark brown, granular and dull. Polygonum viviparum L. 

 B. scopuUna Greene. Alpine, arctic, and subarctic swamps: Greenl.— N.H. — 

 N.M, — Alaska; Eurasia. Alp. — -Mont. Je-Au. 



12. FAGOPYRUM (Tourn.) Mill. Buckwheat. 



Caulescent glabrous annuals. Leaves alternate, petioled; blades hastate or 

 cordate; ocreae oblique, entire. Flowers perfect, several in corymbiform cymes, 

 with slender pedicels subtended by an ocreola. Calyx coroUoid ; sepals 5, equal. 

 Stamens 8. Styles 3; stigmas capitate. Achenes 3-angled, margined or crested. 

 Embryo S-shaped, central. 



1. F. Fagopyrum (L.) Karst. Stem 1-9 dm. high, branched, pubescent at 

 the nodes; leaf-blades hastate, 2.5-8 cm. long; ocreae fugacious; perianth whit- 

 ish; achenes ovoid, 5 mm. long, with pinnately striate faces, acute-angled. F. 

 esculeuium Moench. Escaped from cultivation; native of Eurasia. 



13. ACONOGONUM Reichenb. 



Caulescent herbaceous or rarely suffrutescent plants, with horizontal root- 

 stocks. Leaves fleshy or thin. Inflorescence of axillary and terminal racemes 

 or panicles. Ocreae funnelform, obUque. Pedicels articulate below the peri- 

 anth. Perianth 5-parted, not glandular-punctate. Stamens 5-8, included. 

 Style 3-parted; achenes 3-angled, smooth. Endosperm homy; cotyledons ac- 

 cumbent. 



1. A. phytolaccaefolium (Meisn.) Small. Perennial; stem erect, 1-2 m. 

 high, channeled, branched; leaf-blades lanceolate, 5-15 cm. long, 1-4 cm. wide, 

 acute or acuminate at both ends, sHghtly crisped, ciliate on the margins; inflo- 

 rescence paniculate, leafy; perianth greenish or whitish, 3 mm. long; segments 

 obovate or oblong, rounded; achenes 4 mm. long, broadly ovoid or oval, light 

 chestnut-colored, shining. Polygonum polymorphum and P. alpinum Am. auth. 

 Subalpine and alpme regions: Alaska— Ida.— Nev.— Cahf. ; Asia. Suhmoni, Jl-S. 



14. TRACAULON Raf. Tear-thumb, 



Annual 



Leaves alternate; blades hastate or cordate, membranous, the petioles and 

 veins prickly. Ocreae obUque. Flowers in terminal or axillary spikes, or capi- 

 tate clusters. Sepals 4 or 5, somewhat colored, neither keeled nor winged. 

 Stamens 5-8; filaments not dilated. Ovary 1-celled; styles 2 or 3, partially 

 united. Achenes lenticular or 3-angled, smooth and shining. Endosperm 

 horny; cotyledons accumbent. 



1. T. sagittatum (L.) Small. Annual; stem slender, decumbent or re- 

 chning, 3-15 dm, high, branched, 4-angled, armed on the angles with sharp re- 

 curved prickles; leaves lanceolate or oblong, sagittate at the base, 1-12 cm. long, 

 0.5-3 cm. broad, the lower petioled, the uppermost sessile; perianth white, green, 

 or red, 4 mm. long, 5-parted; achenes 3-angled, black or brownish. Polygonum 

 mgitlatum L. Wet meadows: Newf.— Fla.— Tex.— Sask. Plain, Jl-S. 



15. BILDEaDYKIA Dum. False Buckwheat, Bindweed. 



Annual or perennial twining herbaceous vines. Leaves alternate, with 

 cordate or hastate blades. Ocreae obUque, naked or fringed. Racemes loosely 

 flowered, terminal or axillary^, often paniculate. Sepals 5, green, white, or yel- 

 lowish, the outer two sepals and the intermediate one keeled or winged. Pedi- 

 cels slender, reflexed and articulate. Stamens 8; filaments short, converging. 

 Ovary 1-celled; styles 3, short or almost wanting; stigmas capitate. Achenes 



