BUCKWHEAT FAMILY 237 



6. P. lapathifolia (L.) S. F. Gray. Annual, glabrous or nearly so; stem 

 erect, 3-6 dm. high, thickened at the nodes; leaf -blades broadly or narrowly 

 lanceolate, 5-20 cm. long, attenuate, punctate and ciliolate on the margins; 

 racemes linear-oblong, 2-8 cm. long, drooping, dense; perianth flesh-colored or 

 whitish, 2-2.5 mm. long; achenes lenticular or rarely 3-angled, black or dark 

 brown, slightly granular, shining. Polygonum lapathifoliurn L. Wet places: 

 Que. — Fla. — Calif. — -B.C.; Mex., W.Ind.; Eurasia. Plain — Suhmont. Jl-0. 



7. P. incana (Schmidt) S. F. Gray. Annual; stem erect, 1-4 dm. high, 

 shghtly scurfy; leaf -blades lanceolate or oblong, acute or obtuse; racemes oblong, 

 1-3 cm. long, erect or only slightly nodding; peduncles with sessile glands; peri- 

 anth 2-2.5 mm. long, greenish or pinkish white; achenes lenticular, dark brown, 

 shining. Polygonum incanum Schmidt. Wet places and swamps: Newf. — • 

 N.Y.— Colo.— B.C.; Eu. Plain— Submoyit. Je-S. 



8. P. Persicaria (L.) Small. Annual, glabrous or puberulent; stem erect, 

 2-8 dm. high, usually branched; leaf-blades lanceolate or linear-lanceolate, 2-18 

 cm. long, acuminate, conspicuously^ punctate, usually with a lunar or triangular 

 spot in the middle; racemes oblong or ovoid, 1-3 cm. long, 0.5-1 cm. thick, 

 mostly erect; perianth aboat 2.5 mm. long, pink or purple; achenes lenticular 

 or Spangled, smooth and shining. Polygonum Persicaria L. Lady's ThujMb. 

 Waste places and rich soil : Newf. — Fla. — -Calif. — B.C.; Mex.; Eu. Plain — Sub- 

 mont. My-S. 



9. P. punctata (Ell.) Small. Annual or perennial, mostly glabrous through- 

 out; stem erect, or creeping at the base, 3-10 dm. high, more or less branched; 

 leaf-blades lanceolate to linear-lanceolate, 5-15 cm. long, acuminate, conspicu- 

 ously punctate; raceme hnear, erect, 1-6 cm. long, somewhat interrupted below; 

 perianth greenish, about 2 mm. long, conspicuously glandular-punctate; achenes 

 lenticular or 3-angled, black, smooth and shining. Polygonum punctatum EU. 

 P. ac7-e H.B.K., not Lam. Smartweed. Swamps and wet places: Me. — Fla. — 

 Calif.— Wash.; Mex., C.Am., W.Ind., and S.Am. Plain. Mr-D. 



10. P. Hydropiper (L.) Opiz. Annual, glabrous; stem erect or assurgent, 

 2-6 dm. high, simple or branched, sometimes reddish; leaf-blades ovate-lance- 

 olate or lanceolate, 1.5-9 cm. long, acute, more or less papillose, punctate; 

 racemes hnear, 2-6 cm. long, interrupted and drooping; perianth greenish, 2.5-3 

 mm. long, glandular; achenes lenticular or 3-angled, dark brown, strongly granu- 

 lar and dull. Polygonum Hydropiper L. Water Pepper. Wet places: Newf. 

 — Ga. — Calif. — B.C.; Mex. and C.Am.; nat. from Eu. Plain. Je-S. 



11. BISTORTA (C. Bauhin) Mill. Bistort. 



Perennials, with thickened horizontal rootstocks and simple stems. Basal 

 leaves long-petioled ; stem-leaves short-petioled or sessile, narrow, entire. Ocreae 

 cylindric, hyahne, never ciliate, oblique at the summit. Inflorescence a solitary 

 spike-like raceme, sometimes bearing bulblets at the base. Pedicels articulate 

 at the base of the perianth. Perianth 5-parted, not glandular-punctate. Sta- 

 mens 8, exserted. Style usually 3-parted; achenes triangular or rarely lenticular. 

 Endosperm horny; cotyledons accumbent. 



Racemes not viviparous, not bulblet-bearing, oblong, 1-2 cm. thick. 



Perianth 5-6 mm. long; leaf-blades lanceolate, oblong, or oblanceolate. 



1. B. bistortoides. 



Perianth 3-4 mm. long; basal leaf-blades linear. 2. B. linearifolia. 



Racemes viviparous, bulblet-bearing below, hnear, 5-8 mm. thick. 3. B. vivipara.\ 



1. B. bistortoides (Pursh) Small. Stem erect, 2-7 dm. high, simple; blades 

 of the basal leaves 10-25 cm. long, 0.5-3 cm. broad, acute or obtuse, glabrous on 

 both sides or scabrous-puberulent beneath; stem-leaves lanceolate, sessile; 

 raceme oblong, 1-6 cm. long, 1-1.5 cm. thick, densely flowered; perianth light 

 rose-colored to white; achenes light brown, smooth and shining. Polygonum 

 bistortoides Pursh. B. calophylla, B. glastifolia, and B. lilacina Greene. Wet 

 meadows and swamps: Mont. — N.M.^Calif. — B.C. Alp. — Mont. Je-S. 



2. B. linearifolia (S. Wats.) Greene. Stem slender, 1-3 dm. high; basal 

 leaf-blades 3-4 cm. long, acute; cauUne leaves linear-lanceolate to linear, sessile; 



