62 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 



[Plate 18.] 

 i8. Polygonum longistylum Small. 

 Polygonmn hjwjktijJum. Small, Bull. Torr. Club, 1: 169 (1894). 



Annual or perennial, slender, glabrous except the upper branches and peduncles. 

 Stem erect, :3-0 dm. long, branched throughout, somewhat enlarged at the nodes, more 

 or less channeled, becoming woody below; leaves varying from lanceolate to narrowly 

 lanceolate or sometimes ovate-lanceolate, 3-10 cm. long, .5-2 cm. broad, acuminate at 

 both ends, undulate, more or less ciliate, somewhat crisped, petioled; petioles .5-1.2 cm. 

 long; ocrese cylindric, or funnelform at branching nodes, truncate, entire, thin, brittle, 

 soon falling away; inflorescence terminal, paniculate, glandular and pubescent, consist- 

 ing of spicate often geminate racemes; racemes cylindric, 2-8 cm. long, 1 cm. thick, 

 erect, many-flowered but not dense, conspicuous; ocreolse funnel-form, 2-2.5 mm. long, 

 their margins hyaline; pedicels slender, 3 mm. long, somewhat angled; calyx mostly 

 lilac, 4 mm. long, five-parted to below the middle, the segments oblong, obtuse ; stamens 

 varying from six to eight, included; style 3-3.5 mm. long, two-parted to below the mid- 

 dle, slender, conspicuously exserted, the stigmas black ; achene lenticular, 2.5 mm. long, 

 broadly ovoid, long-pointed, shghtly gibbous on the sides, dark brown or black, slightly 

 granular, somewhat shining or dull. 



Southern Missouri, south to Louisiana and New Mexico. 



