Polygonum. 



POLYGON ACEiE. 



151 



6 - 8 ; styles 2 - 3 ; achenium lenticular or triquetrous, roughish. — Linn. sp. 1. p. 361 ; 

 Michx.fl. 1. p. 238 ; Bigel.Jl. Bost. p. 155 ; Meisn. I. c. p. 76. P. hydropiperoides, Pursh, 

 fl. 1. p. 270. P. punctatum, Ell. sk. 1. p. 455 ; Beck, hot. p. 301 ; Darlingt. Jl. Cest. 

 p. 248. 



Annual. Stem 12 - 18 inches high, sometimes assurgent, often flexuous, smooth. Leaves 

 2-4 inches long and about half an inch wide, tapering to a point, narrowed at the base into 

 a short petiole. Ochreag purplish, with scattered appressed hairs on the sides ; the fringed 

 summit about one-third the length of the tube. Spikes almost filiform, at first nodding, finally 

 almost erect. Bracts turbinate-cylindrical. Calyx greenish white, covered with minute round 

 flat glands, 3 - 5-parted. Styles united below, recurved above : stigmas capitate. Achenium 

 ovoid-lenticular or ovoid-triangular, black. 



Low moist grounds which are occasionally overflowed, and along ditches ; very common. 

 August - September. The whole plant is very acrid, and will cause sores if applied to the 

 skin. In Europe it is sometimes used for dyeing woollen cloth of a yellow color. There 

 can be little doubt of our plant being identical with the P. Hydropiper of Europe. 



***** Tovara, Adans. Flmi:crs pcntandrous : calyx unequally i-parlcd, somewhat gibbous ■■ styles 2, distinct, oblique, 

 recurved at the summit : achenium ovate, biconvex. — Floivers in a very long virgale spike, one or two from each bract. 



13. Polygonum Virginianum, Linn. Virgate Persicaria. 



Stem simple ; leaves ovate-lanceolate, acuminate ; spike terminal, very long and slender ; 

 flowers distant and mostly solitary, pentandrous, somewhat recurved ; calyx a little gibbous ; 

 styles 2, distinct, rigid, oblique ; achenium obovate, lenticular. — Linn. sp. 1. p. 360; Michx. 

 fl. 1. p. 238 ; Pursh, fl. 1. p. 270 ; Ell. sk. I. p. 454 ; Torr. fl. 1. p. 403 ; Bigel.Jl. Bost. 

 p. 156; Meisn. I. c. p. 81. t. 3.f. N ; Beck, hot. p. 301 ; Darlingt. fl. Cest. p. 248; Hook, 

 fl. Bor.-Am. 2. p. 132. 



Perennial. Stem (including the spike) 2-4 feet high, erect, pubescent above, angular. 

 Leaves 3-6 inches long and 1^-3 inches wide, thin, smoothish except on the margin, 

 which is bristly-ciliate : petiole about half an inch long. Ochreas truncate, hairy, ciliate at 

 the summit. Spike 12 - 18 inches long, naked, mostly simple, virgate ; the sheaths 3-6 

 lines apart, with usually a single pedicel growing from each. Calyx somewhat gibbous above, 

 of a greenish white or pale rose-color, 4-parted. Stamens 5, somewhat unequal. Styles 

 rigid, parallel, exserted when in fruit, bent obliquely downward at the base so as to form an 

 obtuse angle with the ovary ; the summits recurved : stigmas minute. Achenium large, 

 strongly convex on both sides, brownish and shining when mature, beaked with the persistent 

 styles : embryo slightly curved against one of the edges of the albumen ; the cotyledons 

 oblong, accumbent. 



Woods and thickets, in rich soil ; not rare. Fl. July - August. Fr. September. A very 

 distinct species, and remarkable for the structure of the flower. It was long ago made a 

 separate genus by Adanson, and more recently by Rafinesque. 



