120 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 
[PxLatE 47. ] 
47. Polygonum Sawatchense Small. 
Polygonum Sawatchense Small, Bull. Torr. Club, 20: 2135 (1893). 
Annual, usually slender, glabrous, more or less scurfy or papillose throughout, of a 
dull green color. Stem erect, .5—-2 dm. long, nearly simple or branched from or near the 
base, minutely ridged, obscurely four-angled and four-winged below the ocreae; leaves 
oblanceolate, narrowly obovate, or almost linear near the ends of the branches, .5—2 em. 
long, 1-6 mm. broad, acute, sessile, acuminate at the base, flat or revolute, often much 
the same length even to the ends of the stems, joined to the ocreae by conspicuous articu- 
lations, midrib prominent on the lower surface and often wing-like; ocreae funnelform, 
oblique, 4-6 mm. long, two-parted, at length lacerate to the middle; inflorescence axil- 
lary, consisting of clusters with from two to four flowers and extending to the base of the 
plant; pedicels 2 mm. long; calyx green, 2-3 mm. long, five-parted to near the base or 
to below the midde, the segments oblong, obtuse, only slightly lighter-colored on the 
margins; stamens 6-8; style almost wanting, stigma three-cleft, included; achene tri- 
quetrous, 2.5-2.8 mm. long, oblong, rather obtuse at both ends or sometimes acute at the 
apex, black, very smooth and shining. 
Dakota to Washington south to Colorado. 
