378 POLYGONACEAE 



blades varying from broadly lanceolate to narrowly lanceolate, sometimes oblong-lanceolate, 

 5-20 cm. long, attenuate to the apex from the broadest part, acuminate at the base, ciliate, 

 inconspicuously but thickly punctate, the petiole and midrib slightly hispid, the latter and 

 the lateral nerves prominent beneath : ocreae 1-2 cm. long, striate or ribbed, brittle, 

 slightly ciliate when young, at length eciliate : racemes linear, 2-8 cm. long, mostly 

 drooping, dense : ocreolae funnelform, 2 mm. long, very oblique, acute : calyx flesh- 

 colored or whitish, 2-2.5 mm. long: stamens 6 : achenes lenticular, 2-2.5 mm. long, very 

 broadly oblong or broadly ovoid, biconcave, brownish or black, slightly granular but 

 usually shining. [ Polygonum lapathifolium L. ] 



In waste places, throughout North America except the extreme north, Mexico, Central America 

 and the West Indies. Apparently mainly introduced from Europe. 



8. Persicaria s6geta (H.B.K. ) Small. Perennial, pubescent or glandular about 

 the inflorescence. Stem erect, 4-8 dm. long, enlarged at the nodes : leaf-blades nar- 

 rowly lanceolate. 6-16 cm. long, acuminate at both ends, sometimes undulate and slightly 

 crisp'ed, glabrous, except occasional short stout hairs on the midrib, and the ciliate margin ; 

 petioles about 1 cm. long: ocreae 1-1.5 cm. long, those on the lower part of the stem 

 glabrous, the upper ones pubescent or glandular, fringed with short bristles: racemes 

 erect, 2-4 cm. long, cylindric, rather loosely flowered : ocreolae funnelform, 2-2.5 mm. 

 long, oblique, coriaceous with a somewhat membranous edge: calyx 2-2.5 mm. long : 

 sepals oblong, obtuse : stamens 6 or 7 : achenes lenticular, 2.5 mm. long, ovoid, usually 

 somewhat plano-concave, rather long-tipped, dark brown, minutely granular, dull. [Poly- 

 gonum segetum H.B.K.] 



In low grounds, Louisiana, Mexico and the West Indies. Also in Colombia. 



9. Fersicatia persicarioides (H.B.K.) Small. Perennial, nearly glabrous or 

 strigillose. Stem erect or decumbent and creeping, 3-7 dm. long : leaf-blades lanceolate 

 or often linear-lanceolate, 3-20 cm. long, acuminate at both ends, glabrous or pubescent 

 with scattered hairs, especially on the midrib, ciliate, punctate, short-petioled or subsessile : 

 ocreae 1-2 cm. long, glabrous or sparsely strigillose, inconspicuously fringed with short 

 bristles : racemes erect, 2-6 cm. long, narrowly oblong or linear, rather loosely flowered : 

 ocreolae funnelform, oblique, 3 mm. long, fringed with a few short bristles or naked, often 

 glandular or scurfy about the summit : calyx 2-3 mm. long, rose-color tinged with green: 

 sepals oblong, obtuse : stamens 8 or fewer : achenes lenticular, biconvex and more or less 

 gibbous, or 3-angled, 2.5-3 mm. long, narrowly ovoid or sometimes broadly oblong, rather 

 long-tipped, black, somewhat granular but shining. [Polygonum persicarioides H.B.K.] 



On plains or prairies, Nebraska, Texas, New Mexico and Mexico. Also in South America. 



10. Persicaria Persicaria ( L. ) Small. Annual, glabrous or puberulent. Stem erect or 

 sometimes spreading, 2-8 dm. long : leaf -blades varying from lanceolate to linear-lanceolate, 

 2-18 cm. long, acuminate at both ends, entire or sometimes eroded, often somewhat ciliate, 

 conspicuously punctate, generally with a dark triangular or lunar spot in the middle : 

 ocreae 1-1.5 cm. long, nearly glabrous or with short hairs on the ridges, usually conspicu- 

 ously fringed with short bristles : racemes oblong or ovoid, 1-3 cm. long, 0.5-1 cm. thick, 

 mostly erect, densely-flowered : ocreolae funnelform, 1.5-2 mm. long, oblique, smooth or 

 nearly so, fringed with short bristles: calyx about 1.5 mm. long, varying from pink to 

 dark purple or sometimes red or greenish : sepals obtuse : stamens generally 6 : achenes 

 lenticular, biconvex, often gibbous, or 3-angled, 2-2.5 mm. long, broadly ovoid, pointed, 

 black, smooth and shining. [Polygonum Persicaria L.] 



In waste places, throughout temperate and tropical North and South America. Naturalized from 

 Europe. LADY'S THUMB. 



11. Persicaria Opelousana ( Ridd. ) Small. Perennial, slender and rather strict. 

 Stem erect or ascending, 3-9 dm. long, glabrous, becoming woody below : leaf -blades vary- 

 ing from linear-lanceolate to linear, 3-10 cm. long, glabrous or with a few stout hairs espe- 

 cially on or about the midrib, ciliate : ocreae 1-1.5 cm. long, strigose, fringed with long 

 bristles : racemes linear, 1.5-4 cm. long, erect, not densely flowered : ocreolae funnelform, 

 2.5 mm. long, slightly oblique, conspicuously fringed with long bristles : calyx 1-1.5 mm. 

 long, white : sepals oblong, obtuse : stamens 8 or fewer : achenes 3-angled, or rarely 4- 

 angled, about 2 mm. long, varying from broadly ovoid to obovoid, black, smooth and 

 shining. [Polygonum Opelousanum Ridd.] 



In swamps, southern Missouri and the Indian Territory to Louisiana, Texas and Mexico. 



12. Persicaria hydropiperoides ( Michx. ) Small. Perennial, glabrous or sometimes 

 slightly strigillose, often tinged with red throughout. Stem erect or the base decumbent 

 and creeping, 3-9 dm. long : leaf-blades lanceolate or oblong-lanceolate, sometimes linear- 

 lanceolate, 4-13 cm. long, acute at both ends, ciliate, papillose on the lower surface, short- 

 petioled, the midrib clothed with short hairs : ocreae 1-1.8 cm. long, strigose, fringed with 



