78 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 
[PuatEe 26.] 
26. Polygonum Opelousanum Riddell. 
Polygonum Opelousanwm Riddell; Small, Bull. Torr. Club, 19: 554 (1892). 
Perennial, slender and rather strict. Stem erect or ascending, 3-9 dm. long, spar- 
ingly or considerably branched, glabrous, becoming woody below; leaves varying from 
linear-lanceolate to linear, 3-10 em. long, .8-.7 em. broad, glabrous or with a few stout 
hairs especially on or about the midrib, ciliate, sessile; ocreae cylindric or funnelform 
at branching nodes, 1-1.5 cm. long, strigose, fringed with long bristles; inflorescence pan- 
iculate, the ultimate divisions ending in spicate often more or less geminate racemes; 
racemes almost linear, 1.5—-4 cm. long, erect, not densely flowered; ocreolae funnelform, 
2.5 mm. long, slightly oblique, conspicuously fringed with long bristles; pedicels 2.5-3 
mm. long, angled; calyx 1-1.5 mm. long, white, five-parted to below the middle, the 
segments oblong, obtuse; stamens eight or fewer, included; style three-parted to below 
the middle, about .6 mm. long; achene triquetrous or rarely tetragonous, about 2 mm. 
long, varying from broadly ovoid to obovoid, black, smooth and shining. 
Southern Missouri and Indian Territory south to Louisiana, Texas and Mexico. 
