P OL YG ON A CEA E. 36 1 



stamens 6; style 2-parted to near the base; achene ovoid-oblong, lenticular, about 



2 mm. long, flat or biconcave, smooth, shining. In wet soil, Vt. to 111. and Neb., 

 south to Fla. and La. June-Sept. 



7. Polygonum lapathifolium L. Dock-leaved or Pale Persicaria. 

 (I. F. f. 1324.) Annual, stem erect or ascending, swollen at the nodes, 3-9 dm. 

 high, the peduncles and pedicels glandular. Leaves lanceolate or oblong- 

 lanceolate, 5-25 cm. long, usually broader than those of the preceding, attenuate 

 to the apex, acuminate at the base, short-petioled, ciliate, inconspicuously punctate; 

 ocreae cylindric, ribbed or striate; racemes panicled, 2.5-10 cm. long, drooping, 

 narrow, rather dense; calyx pink, greenish or white, 5 -parted; stamens 6; style 

 2-parted to below the middle; achene broadly oblong or ovoid, lenticular, 2 mm. 

 long, brownish or black, slightly reticulated but shining, its faces concave. In 

 waste places, throughout temperate N. Am. Nat. from Europe. Sometimes a 

 troublesome weed. Native also of Asia. June-Sept. 



Polygonum lapathifolium nodosum (Pers.) Small. Generally robust and glabrous ; 

 stem stout, reddish, purple spotted and with a purple ring below each ocrea, much 

 thickened at the nodes ; leaves conspicuously punctate ; racemes 2.5-7.5 cm - ^ on Sy l ess 

 drooping, often erect ; achene slightly larger. Occasional in the range of the type. 



Polygonum lapathifolium incanum (Schmidt) Koch. Low; stem slender, erect, 

 5-30 cm. high, slightly scurfy ; leaves lanceolate, ovate or oblong, usually narrowed at 

 the base, white-tomentose beneath, glabrous above ; racemes 1-4 cm. long. In waste 

 places, N. S. to Ont., N. Y., and Br. Col. 



8. Polygonum Pennsylvanicum L. Pennsylvania Persicaria. (I. F. f. 

 1325.) Annual, glabrous below; stem erect, 3-9 dm. tall, the upper parts, the 

 peduncles and pedicels glandular. Leaves lanceolate, acuminate at the apex, 

 petioled, ciliate, 5-30 cm. long, the upper sometimes glandular beneath; ocreae 

 cylindric, naked, glabrous; racemes panicled, erect, thick, oblong or cylindric, 

 dense, 2.5-5 cm - ^ on gi calyx dark pink or rose-color, 5-parted; stamens 8 or fewer; 

 style 2-cleft to about the middle; achene orbicular or mostly broader than high, 



3 mm. long, short-pointed, lenticular, smooth, shining. In moist soil, N. S. to 

 Ont., Minn., Fla. and Tex. July-Sept. 



9. Polygonum longistylum Small. Long-styled .Persicaria. (I. F. f. 

 1326.) Annual or perennial, glabrous except the glandular upper branches and 

 peduncles; stem erect, rather slender, 3-9 dm. tall. Leaves lanceolate or ovate- 

 lanceolate, 2.5-15 cm. long, acuminate at both ends, petioled, their margins 

 undulate, slightly crisped, more or less ciliolate; ocreae cylindric, entire, brittle; 

 racemes panicled, sometimes geminate, 2.5-8 cm. long, rather dense, erect; calyx 

 lilac, 5-parted to below the middle, the lobes petaloid; stamens 6-8, included; 

 style 2-parted, slender, conspicuously exserted; stigmas black; achene broadly 

 ovoid, lenticular, slightly gibbous on both sides, long-pointed, black, granular, 

 but somewhat shining, 2.5 mm. long. In moist soil, S. 111. and Mo. to La. and 

 N. Mex. Aug. -Oct. 



10. Polygonum Persicaria L. Lady's Thumb. (I. F. f. 1327.) Annual, 

 glabrous or puberulent ; stem erect or ascending, 1.5-6 dm. high. Leaves 

 lanceolate or linear-lanceolate, 2-15 cm. long, acuminate at both ends, conspicuously 

 punctate, usually with a dark triangular or lunar blotch near the centre, their 

 margins entire or slightly eroded, often ciliate; ocreae cylindric, nearly glabrous, 

 fringed with short bristles; racemes solitary or panicled, 1-5 cm. long, ovoid or 

 oblong, dense, erect ; calyx pink or dark purple; stamens mostly 6; style 2-3- 

 parted to below the middle; achene broadly ovate and lenticular, often gibbous or 

 3-angled, 2-2.5 mm - l° n g> smooth and shining. In waste places, throughout N. Am. 

 except the extreme north. Nat. from Europe. Often an abundant weed. June- 

 Oct. 



11. Polygonum persicarioides H. B. K. Southwestern Persicaria. 

 (I. F. f. 1328.) Perennial, glabrous or minutely pubescent; stem erect, decumbent 

 or creeping, 3-9 dm. long. Leaves lanceolate or linear-lanceolate, acuminate at 

 both ends, punctate, 4-25 cm. long ; ocreae cylindric, glabrous, or sparingly 

 strigillose, fringed with short bristles ; racemes more or less panicled, erect, 

 2.5-7.5 cm. long, narrowly oblong or linear, loosely flowered; calyx rose-color 

 tinged with green, 5-parted to below the middle; stamens 8 or fewer; style 2-3- 



