Polygonum. POLYGONACE^. 149 



achenium compressed, smooth. — Linn. sp. 1. p. 361 ; Michx. fl. 1. p. 240 ; Torr. fl. 1. 

 p. 403 ; Meisn. I. c. p. 67; Hook. fl. Bor.-Am. 2. p. 131. P. coccineum, Willd. enum. I. 

 p. 429 ; Pursh, fl.\. p. 271. 



var. 1. aquaticum: floating; leaves ovate -lanceolate, smooth or slightly pubescent. P. 

 amphibium, P. aquaticum, Linn. I. c; Hook. Brit. fl. (ed. 4.) 1. p. 164 ; Torr. I. c. P. 

 amphibium, a. natans, Michx. I. c. ; Meisn. I. c. ; Beck, hot. p. 301 ; J^ooil. fl. Bor.-Am. 

 I. c. P. coccineum, var. aquaticum, Pursh, I. c. P. coccineum, Bigel. fl. Bost. p. 157. 

 P. fluitans, Eat. man. hot. ed. 8. p. 368. 



var. 2. terrestre : stem erect or ascending ; leaves elliptical-lanceolate, acute or acuminate, 

 clothed on the lower or on both sides with short rigid appressed hairs, or sometimes very 

 hairy ; ochreae (at least the lower ones) strigose. Torr. I. c. ; Meisn. I c. ; Hook. I. c. ; Beck, 

 I. c; Darlingt. fl. Cest. p. 250. P. amphibium, Bigel. I. c. P. coccineum, var. emersum, 

 Michx. I. c. P. coccineum, var. terrestre, Willd. I. c. ; Pursh, I. c. 



Perennial. Stem in var. 1. long, slender and floating, or thicker and rooting in soft mud ; 

 in var. 2. rather stout, 1-2 feet high. Leaves 4-6 inches long and 1-2 inches wide 

 (smaller in the floating form) : upper ones nearly sessile ; the lower on petioles 3-6 lines 

 long. Ochrese truncate. Spikes 1-3 inches long ; the flowers bright rose-color and showy. 

 Calyx open. Stamens a little exserted : anthers purplish. Styles slender, exserted, united 

 below : stigmas capitate. Nut orbicular-ovate, compressed, dark brown and a little shining. 



Ponds, muddy banks and low grounds ; frequent north and west of the Highlands. The 

 two varieties appear quite distinct when seen in their extreme forms, but they gradually pass 

 into each other ; and the North American plant is certainly identical with the P. amphibium 

 of Europe. It is a troublesome weed in England, in lands reclaimed from marshes. 



9. Polygonum Persicaria, Linn. Lady's-thumb. 



Leaves lanceolate ; ochreae truncate, ciliate ; spikes ovoid-oblong, dense, erect, on smooth 

 peduncles ; flowers mostly hexandrous ; styles two ; achenium compressed, or sometimes 

 obtusely triangular. — Linn. sp. 1. p. 361 ; Engl. hot. t. 756 ; Michx. fl. \. p. 239 ; Pursh, 

 fl.l. p. 271 ; Bigel. fl. Bost. p. 156 ; Torr. fl. 1. p. 405 ; Meisn. I. c. p. 68 ; Beck, bat. 

 p. 302 ; Darlingt. fl. Cest. p. 249 ; Hook. fl. Bor.-Am. 2. p. 132. 



Annual. Plant not acrid. Stem 12-18 inches long, erect, assurgent or decumbent, 

 smooth, somewhat branching. Leaves 2-4 inches long, tapering at each end, rough and 

 hairy on the margin, usually with a darkish lunate or triangular spot near the middle. Stipules 

 fringed with bristly hairs at the summit. Spikes about an inch long ; the bracts turbinate. 

 Flowers rose-color or crimson. Styles united about one-third of their length. Achenium 

 ovate, with a short acumination, usually compressed but sometimes triangular, smooth, black 

 and shining. 



Waste places, gardens, and often in low grounds ; common. Introduced from Europe. 

 July - August. To this species Meisner refers P. lapathifolium, Linn., and P. incanum, 

 WiUd. 



