160 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 
[Puate 67. ] 
68. Polygonum Meisnerianum Beyrichianum (Chamisso & Schlechtendal) Meisner. 
Polygonum Beyrichianum Chamisso & Schlechtendal, Linnaea, 3: 42 (1828). 
Polygonum multangulare Hooker & Arnott, Comp. Bot. Mag. 2: 62 (1836). 
Polygonum Meisnerianum var. Beyrichianum Meisner in Mart. Fl. Bras. 5: 19 (1855). 
Polygonum Chamissounum Steudel; Meisner, Mart. Fl. Bras. 5: 20 (1855). 
Polygonum geniculatum Riddell; Meisner, Mart. Fl. Bras. 5: 20 (1855). 
Perennial, slender and somewhat wiry, nearly glabrous except the inflorescence and 
prickly stem. Stem 5-10 dm. long, reclining, dichotomously branched, somewhat en- 
larged at the nodes, rather sharply angled, the angles mostly armed with recurved 
prickles; leaves linear or linear-lanceolate, subsagittate, 3-15 em. long, .4—-1.5 em. broad, 
acute or acutish, subsessile, cordate and more or less clasping, almost glabrous on the 
upper surface, glabrous beneath except the midrib which is sometimes sparsely pubes- 
cent with prickle-like hairs, glandular-ciliate; ocreae cylindric, 1-2 cm. long, somewhat 
obliquely opened and spreading at the summit, naked, very thin, fringed around the 
base with small recurved prickles; inflorescence dichotomous, more or less compound, 
the ultimate divisions ending in clusters or spicate racemes; peduncles glandular; racemes 
5-1 em. long, few-flowered; ocreolae 1 mm. long, ciliate; pedicels .8-.9 mm. long; calyx 
rose-colored, campanulate, five-parted to the middle, 2-3 mm. long, the segments ovate- 
oblong, obtuse; stamens five, included; style .5 mm. long, three-parted, included; achene 
varying from broadly ovoid to oboyoid, triquetrous, dark brown, smooth and shining, the 
faces convex, the angles obtuse. 
Louisiana to Texas and Mexico southward to Brazil. Also in the West Indies. 
