122 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 
[Piare 48.] 
48. Polygonum tenue Michaux. 
Polygonum tenue Michaux, Fl. Bor. Am. 1: 258 (1805); Persoon, Syn. 1: 439; 
Pursh, Fl. Am. Sept. 270; Eaton, Man. 370; Elliott, Fl. 8. C. and Ga. 1: 454; Sprengel, | 
Syst. 2: 256; Torrey, Fl. 1: 401, Comp. 171; Meisner, Monog. 91 and in DC. Prodr. 14: 
100; Darlington, Florula Cest. 48, Fl. Cest. 248; Hooker, Fl. Bor. Am. 2: 132; Beck, 
Bot. 301; Bigelow, Fl. Bost. 155; Eaton & Wright, N. A. Bot. Ed. 8,367; A. Gray, Man. 
389; Wood, Cl. Bk. Ed. 41, 474, Am. Bot. and Fl. 283; Chapman, FI. S. States, 390; 
Darby, Bot. 8. States, 488; Greene, Bull. Cal. Acad. Sci. 1: 125; Coulter, Man. Bot. 
Rocky Mt. Reg. 319. 
Polygonum linifolium Muhlenberg, Cat. 40 (1813); Barton, Comp. FI. Phil. 1: 186; 
Wood, Cl. Bk. Ed. 41, 474. 
Polygonum filiformis Barton, Comp. Fl. Phil. 1: 186 (1818), not Thunb. 
Polygonum tenue var. commune Engelmann; A..Gray, Proc. Acad. Phila. 75 (1863). 
Annual, slender, glabrous throughout or somewhat scabrous and scurfy about the 
nodes. Stem erect, 1-3 dm. long, simple or much branched, more or less four-angled or 
four-winged below the ocreae; leaves linear or linear-lanceolate, .5-3 em. long, .1-.3 em. 
broad, acuminate or cuspidate, sessile, with two lateral impressions appearing as ribs 
parallel to the midrib, articulated to the ocreae, minutely scabrous on the margin, more 
or less scurfy on the lower surface, sometimes revolute; ocreae funnelform, oblique, 3-15 
mm. long, two-parted, at length lacerate; inflorescence axillary, consisting of clusters 
bearing several flowers or sometimes only one flower at a node; pedicels stout, 1-1.5 mm. 
long; calyx green, 3 mm. long, erect, five-parted to near the base, the segments ovate, 
acutish, with whitish margins; stamens eight, included; style .3-—.4 mm. long, three- 
parted to near the base, the segments diverging, included or protruding slightly beyond 
the calyx; achene triquetrous, 3 mm. long, ovoid, pointed, black, granular about the 
angles, the centres of the faces smooth and shining. 
Canada to Minnesota south to Georgia and New Mexico. 
