252 



OCTANDRIA TRIGYNIA. 



220. POLYGONUM. Persicaria, Bistort, Knot- 

 grass, and Buckwheat. 



Linn.Gen. \95. Juss. S2. Fl.Br. 423. Tourn.t. 290. Lam.t. 315. 



GcETtn. <. 119. 

 Persicaria. Tourn.t. 290. Ga:rtn. t. 119. 

 Bistorta. Tourn.t. 291. 

 Fagopyrum. Tourn. t. 290. Gtsrin. f. 119. 



Nat. Ord. Holeraceae. Linn. 12, e. Polygonece. Juss. 28. 



Cal. inferior, turbinate, more or less coloured, in 5 deep, 

 ovate, obtuse, permanent segments. Cor. none. Filam. 

 various in number, from 5 to 6, 7, or most generally 8, 

 awl-shaped, very short. Antli. roundish, incumbent. 

 Germ, superior, roundish, either triangular or com- 

 pressed. Styles generally 3, in those with a compressed 

 germen only 2, thread-shaped, very short, in some species 

 partly combined. Stigmas simple. Peric. none, except 

 the closed calyx. Seed solitary, eidier triangular or com- 

 pressed, pointed ; embryo enveloped in a farinaceous al- 

 bumen. 



Generally herbaceous, with knotty, alternately branching 

 stems. Leaves alternate, siinple, revolute in the bud; 

 either sheathing at the base, or attached to an interior, 

 membranous, ribbed, tubular or sheathing, stipula. Fl. 

 axillary, or terminal, simply stalked, clustered, or spiked ; 

 either red, or particoloured with red, green and white. 

 Seed brown, often polished. 



* Styles usually but 2. 



L P. amphibium. Amphibious Persicaria. 



Styles two, united half way up. Stamens five. Spike ovate. 



P. amphibium. Linn. Sp. PL 5 1 7. Ifllld. v. 2. 443. Fl. Br. 423. 



Engl. Bot.v.7.t. 435. Curt. Lond.fasc. 4. t. 28. Hook. Scot. 121, 



Fl. Dan. t. 282. 

 P. n. 1565. Hall. Hist. V. 2. 261. 

 Persicaria salicis folio perennis. Raii Syn. 145, 

 Potamogeton salicis folio. Bauh.Pin. 193. 

 P. angustifolium. Ger. Em. 821 ./. 

 P. altera. Dalech. Hist. 1008./. 

 P. sive Stachyites. Lvb. Ic. 307./, 



