CLASS VIII. ORDER III. 167 



Polygonum Virginicum. Virgated Polygonum. 



Flowers pentandroiis, digynoiis, unequal, leaves 

 broad-oval; spikes virgated with remote flowers. 



This species is distinguished hy its very long, virgated, flow- 

 ering hranches. Stem two or three feet high, somewhat hairy. 

 Sheaths hairy, ciliate, entire or split. Leaves on short petioles, 

 ovate lanceolate, acuminate. Peduncles or flowering branches 

 often a foot long. Flowers small, greenish, scattered, with gen- 

 erally five stamens. Seed compressed, tipt with the deflected 

 cloven style. — Woods. — June, July. — Perennial. 



PoiA'GONUM AMPHiBiuM. L. Aniphihious Polygonum. 



Stamens five, styles two, half united ; leaves ob- 

 long-lanceolate, acute, rough at the edge ; spike 

 cylindrical. 

 Syn Polygonum amphibium. (i. emersum. Mx. 



Distinct from the following species by its leaves, which are 

 generally lanceolate, though sometimes rounded at base, the 

 edges ciliate-serrulate, so as to feel rough, the veins also having 

 sometimes the same character. Stem fleshy, decumbent, root- 

 ing. Sheaths tubular, smooth, entire, the lower ones sometimes 

 ragged or ciliate. Spike solitary, terminal, at first ovate, at 

 length cylindrical. Flowers large, rose colored. — Borders of 

 ponds and ditches, growing above water. — August. — Perennial. 



It agrees perfectly with European specimens. 



Polygonum coccineum. Willd. Floating Polygonum. 



Stamens five, styles two, half united; leaves ob- 

 long, smooth throughout, lucid; spike cylindrical. 

 Syn. Polygonum amphibium. «. nutans. Mx. 



A more perfectly aquatic species than the last, better distin- 

 guished from it by the entire smoothness of its leaves than 

 by the characters usually given. Stem rooting at the joints. 

 Leaves mostly floating, green and shining above, purplish be- 

 neath, without hairs, commonly oblong and obtuse at both ends 

 sometimes hearted at base and subacute. Sheaths entire, the 

 lower ones sometimes ragged. Spike terminal, ovate by the 



