Annual or perennial herbaceous plants, becoming somewhat woody below. Stem mostly erect, virgate, simple or virgately branched. Leaves alternate, membranous, acute at both ends, continuous with the ocreae. Ocreae cylindric, fringed with bristles. Flower-clusters not dense, remote. Racemes linear, very long and wand-like, conspicuously interrupted.

Calyx more or less colored, somewhat curved. Sepals 4, the 2 lateral ones overlapping the others. Stamens 4, and alternating with the sepals, or 5, the fifth one opposite the lower sepal; filaments barely flattened, erect or slightly spreading. Styles 2, conspicuously exserted, recurved or curled. Achencs lenticular, strongly biconvex, brown or cream-colored, smooth and shining. Endosperm horny. Cotyledons accumbent. [Derivation uncertain.]

Two known species, the following typical, the other Japanese,

1. Tovara Virginiana (L.) Raf. Virginia Knot Weed

Fig. 1629

Polygonum virginianum L. Sp. PI. 360. 1753. Tovara virginiana Raf. Fl. Tell. 3: 12. 1836.

Plants nearly glabrous or strigose-pubescent, stem erect or arching, simple or branched above, 1°-4° tall. Leaves ovate or elliptic-ovate or ovate-lanceolate, short-petioled, acuminate at the apex, 2'-6' long, sparingly ciliate; ocreae cylindric, strigose, fringed with short bristles; racemes spicate, erect, terminal and axillary, naked, greatly elongated and interrupted, sometimes 12' long; calyx curved, greenish or rose-color, 4-cleft; stamens 5; style long, exserted, 2-parted to the base, its branches at length curled; achene 2" long, ovate-oblong, lenticular, strongly biconvex, dark brown or cream-colored, smooth, shining.

In woods. Nova Scotia to Minnesota, south to Florida and Texas. Ascends to 4000 ft. in North Carolina. July-Nov.