POLYGONACEAE 375 



silvery when young, becoming lacerate and brown with age : clusters of several flowers : 

 pedicels 2-2.5 mm. long: calyx greenish, 3 mm. long: sepals oblong, obtuse, paler or 

 whitish on the margins, the outer corrugated at maturity : stamens 6 or sometimes 5 : 

 achenes 3 mm. long, pyramidal-ovoid or broadly ovoid, dark brown, granular and dull. 

 In open grounds, Ontario to the Northwest Territory, Georgia, Texas and Colorado. 



5. Polygonum camporum Meisn. Perennial or sometimes annual, rarely glaucescent, 

 turning brown or black in drying. Stem erect or ascending, 6-10 dm. long, sometimes 

 much branched and straggling : leaf-blades varying from linear-lanceolate to oblong, 1-3 

 cm. long, sometimes oblanceolate, obtuse or acute, fugacious or rarely somewhat persistent, 

 conspicuously nerved beneath : ocreae 3-5 mm. long, two-lobed when very young, silvery, 

 at length dark brown, soon becoming much lacerate and falling away : clusters several- 

 flowered : pedicels slender, 2-3 mm. long : calyx greenish, 3 mm. long : sepals oblong : 

 stamens 8 : achenes 3 mm. long, broadly ovoid, black or dark brown, smooth and shining. 



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



6. Polygonum ramosissimum Michx. Annual, somewhat scurfy, bright green or 

 yellowish green. Stem erect or ascending, 1-3 dm. long, somewhat virgate, the branches 

 ascending or spreading: leaf-blades lanceolate, oblong or linear-oblong, 0.7-4 cm. long, 

 acuminate at both ends or acute at apex, persistent, nerves either prominent or indistinct 

 on the lower surface : ocreae 0.5-1.5 cm. long, very early becoming lacerate, silvery, or at 

 length turning brown : clusters several -flowered : pedicels 1.5-2 mm. long : calyx greenish 

 or yellowish, about 3 mm. long : sepals narrowly oblong : stamens 6 or fewer, sometimes 

 only 3 : achenes 3 mm. long, ovoid, pointed, mostly included or rarely slightly protruding 

 beyond the calyx, black, somewhat granular, not shining. 



In saline or sandy soil, Northwest Territory to California, New Mexico, Texas and Illinois. Also 

 along the Atlantic Coast from Maine to New Jersey. 



7. Polygonum t6nue Michx. Annual. Stem erect, 1-3 dm. long, with scabrous and 

 scurfy nodes, four-winged below the ocreae : leaf- blades linear or linear-lanceolate, 0.5-3 

 cm. long, acuminate or cuspidate, with two lateral impressions appearing as ribs parallel 

 to the midrib: ocreae 3-15 mm. long, two-lobed, at length lacerate: clusters bearing 

 several flowers, or sometimes only one flower at a node : pedicels stout, 1-1.5 mm. long : 

 calyx green, 3 mm. long, erect : sepals ovate, acutish, with whitish margins : stamens 8 : 

 achenes 3 mm. long, ovoid, pointed, black, granular about the angles, the center of each 

 face smooth and shining. 



In dry or stony soil, Ontario to Minnesota, Georgia and Arkansas. 



8. Polygonum Douglasii Greene. Annual, sometimes glaucescent. Stem erect, 2-4 

 dm. long, with more or less scabrous nodes : leaf-blades oblong or narrowly lanceolate, 1-5 

 cm. long, obtuse, acute or cuspidate, flat, at least without lateral impressions : ocreae 

 10-14 mm. long, two-lobed, at length lacerate : clusters several -flowered, or occasionally 

 only a single flower at a node : pedicels 2-3 mm. long, reflexed and at length deflexed : 

 calyx 3-4 mm. long, drooping : sepals oblong, obtuse, with whitish or rose-colored mar- 

 gins and a dark rib in the middle : stamens 8 : achenes 3-4 mm. long, oblong or rarely 

 ovoid-oblong, black, smooth and shining. 



In dry soil, Northwest Territory to California, New Mexico and Indian Territory, east through 

 Ontario to Vermont and New York. 



7. TOVARA Adans. 



Annual herbaceous plants, becoming somewhat woody below. Stem mostly erect, 

 virgate, simple or virgately branched. Leaves alternate : blades membranous, short, 

 acute at both ends, continuous with the ocreae. Ocreae cylindric, fringed with bristles. 

 Flower-clusters not dense, remote. Racemes linear, very long and wand-like, conspicu- 

 ously interrupted. Calyx more or less colored, somewhat curved. Sepals 4, the 2 lateral 

 ones overlapping the others. Stamens 4, and alternating with the sepals, or 5, the fifth 

 one opposite the lower sepal : filaments barely flattened, erect or slightly spreading. Styles 

 2, conspicuously exserted, recurved or curled. Achenes lenticular, strongly biconvex, 

 brown or cream-colored, smooth and shining. Endosperm horny. Cotyledons accumbent. 



1. Tovara Virginiana (L. ) Adans. Annual, sometimes strigose throughout. Stem 

 erect or reclining, 3-13 dm. long, virgate, simple or virgately branched, especially above : 

 leaf-blades ovate, elliptic-ovate or ovate-lanceolate, 3-16 cm. long, acuminate, acute at the 

 base ; petioles 1-2.5 cm. long : ocreae cylindric, 0.5-1.5 cm. long, fringed with short bristles : 

 racemes 1-6 dm. long, naked, much interrupted, virgate : ocreolae funnelform, 2. mm. long, 

 fringed with short bristles : pedicels 3 mm. long, somewhat reflexed, conspicuously articu- 



