212 



N. Ord. POLYQONACE^. Lindl., Veg. K., p. 642 ; Le Maout & Dec., 

 p. 631. 



Tribe Polygonece. 



Genus Polygonum,* Linn. Meisner, in DC. Prod., xiv, pp. 

 83-143. Species 215, natives of all parts of the globe. 



212. Polygonum Bistorta,t Linn., 8p. PL, e d. I, p. 360 



(1753). 



Bistort. Snake-weed. 



Figures. Woodville, t. 232 ; Hayne, v, t. 19 ; Steph. & Ch., t. 48 ; 

 Nees, t. 105 ; Curt., PI. Londin., fasc. i; Syme, E. Bot., viii, 1. 1243. 



Description. An herbaceous perennial. Eoot- stock cylindrical, 

 woody, about as thick as a finger, widely creeping, much 

 branched, ridged with leaf -scars on the outside, brownish, pale 

 red within, giving off numerous fibrous roots, usually twisted 

 into an S-shape, branches ending in tubers. Stems erect, quite 

 simple, 14 2 ft. high, cylindrical, smooth, striate, slightly thick- 

 ened at the nodes. Radical leaves large, on long stalks, ovate, 

 acute, abruptly constricted at the base and then attenuated into 

 the petiole, margin entire, somewhat undulated; stem-leaves few, 

 alternate, rapidly decreasing in size upwards, blade narrowly 

 ovate, acute, sessile or nearly so, the petiole forming a long 

 tubular sheath round the stem, continued above (for an inch above 

 the blade in the lower leaf) into a scarious entire stipular appen- 

 dage (ocrea) ; all dark green above, glaucous and pubescent on the 

 prominent veins beneath. Flowers arranged in pairs, each couple 

 surrounded at the base by two scarious cuspidate bracts, stalked, 

 articulated to the summit of the smooth slender pedicels, and 

 readily separating from them, one of the two expanding much before 

 the other ; clusters very densely crowded on the upper part of the 

 stem, where they form a solid, cylindrical, oblong, blunt, erect in- 



* Name from iroXvg, many, and yovv, a knee or knot, from the numerous 

 nodes in some species, 

 f Bistorta, the mediseval name, from the twice-twisted root- stock. 



