558 



POLYGONACEAE. 



g. Polygonum longistylum Small. Long-styled Persicaria. (Fig. 1326.) 



Polygonum longistylum Small, Bull. Torr. Club, 

 21: 169. 1894. 



Annual or perennial, glabrous except the glan- 

 dular upper branches and peduncles; stem erect, 

 rather slender, i-3 tall, becoming somewhat 

 wood}- below. Leaves lanceolate or ovate-lan- 

 ceolate, i / -6 / long, acuminate at both ends, peti- 

 oled, their margins undulate, slightly crisped, 

 more or less ciliolate; ocreae cylindric, entire, 

 brittle, soon falling away; racemes panicled, 

 sometimes geminate, i'-4' 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; stig- 

 mas black; achene broadly ovoid, lenticular, 

 slightly gibbous on both sides, long-pointed, 

 black, granular, but somewhat shining, i ' 4 " 

 long. 



In moist soil. Southern Illinois and Missouri to 

 Louisiana and New Mexico. Aug.-Oct. 



10. Polygonum Persicaria L,. L/adj-'s 

 Thumb. (Fig. 1327.) 



Polygonum Persicaria L. Sp. PI. 361. 1753. 



Annual, glabrous or puberulent; stem erect or 

 ascending, simple or much branched, %-2 

 high. Leaves lanceolate or linear-lanceolate, 

 \'-6 f long, short-petioled or nearly sessile, acu- 

 minate at both ends, conspicuously punctate, usu- 

 ally 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, %'-%' 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, \"-\%" long, smooth and shining. 



In waste places, throughout North America, ex' 

 cept the extreme north. Naturalized from Europe- 

 Often an abundant weed. June-Oct. 



ii. Polygonum persicarioides H.B.K. 

 Southwestern Persicaria. (Fig. 1328.) 



P. persicarioides H.B.K. Nov. Gen. 2: 179. 1817. 



Perennial, glabrous or minutely pubescent; stem 

 erect, decumbent or creeping, simple or branched, 

 i-3 long. Leaves lanceolate or linear-lanceolate, 

 acuminate at both ends, punctate, short-petioled or 

 subsessile, lj^ / -io / long; ocreae cylindric, glabrous 

 or sparingly strigillose, fringed with short bristles; 

 spicate racemes more or less panicled, erect, I'-j' 

 long, narrowly oblong or linear, loosely- flowered; 

 calyx rose-color tinged with green, 5-parted to below 

 the middle; stamens 8 or fewer, included; style 2-3- 

 parted to near the base; achene lenticular and 

 biconvex, or 3-angled, more or less gibbous, i" 

 long, ovoid or broadly oblong, short-pointed, black, 

 minutely granular, but shining. 



Nebraska to Mexico; widely distributed in tropical 

 America. June-Sept. 



