CLASS VIII. ORDER II.] POLYGONUM. 671 



conditions, is apt to confuse the student in determining to what species 

 it belongs. It is, wlien growing in water, a pretty showy plant, its 

 spikes of pink flowers continuing a long time in bloom; but when it 

 has established itself upon land, either from the circumstance of drains, 

 &c. being cleared out, or from lands being drained, it has a very 

 different aspect, and becomes a rough erect plant, being in such situa- 

 tions a very troublesome weed, extremely dilficult of extirpation, its 

 long underground stems taking root at every joint, and each joint is 

 capable of producing a separate plant, which puts out an abundance uf 

 others, and thus the plant is continued, although it may not produce a 

 single seed. The roots, which bear some resemblance to Sarsaparilla, 

 are reported by Coste and VVillemet to possess the same properties, and 

 to be used as such in Nancy and Lorraine, even in preference. 



4. P. lapathifo' Hum, Linn. (Fig. 648.) Pale-Jloioered Persicaria. 

 Spikes oblong, cylindrical, dense, erect ; flowers hexandrious, rough, 

 like the peduncles, with glands ; styles two, distinct ; leaves ovate 

 lanceolate, on short petioles; stipules smooth or woolly, the margin 

 short, and sparingly ciliated, 



English Botany, t. 1382.— English Flora, vol. ii. p. 234. — Hooker, 

 British Flora, vol. i. p. 186. — Lindley, Synopsis, p. 212. 



a. Leaves green, smooth, thickly scattered over with glands on the 

 under side. 



/3. rubrum, (Fig. 649.) Stems and flowers red. /3. Curtis Lond. 

 under, t. 25. 



y. maculatum, (Fig. 6.50.) Stem spotted with red. y. Curtis Lond. 

 t. 25. 



J. tomentosum. Leaves hoaa-y beneath. ^, Curtis Lond. under. 

 t. 25. — p. incanum, Schm. boh. n. 391. 



P. f,omentosum. Schrank. Caier. fl. 1. p. 669. 



£, album. Leaves hoary above, woolly beneath. 



Root fibrous. Stem erect or decumbent at the base, frequently with 

 the joints much swelled, branched and leafy, round, smooth, striated. 

 Leaves ovate-lanceolate, or lanceolate, entire or waved, tapering into 

 rough short footstalks, channeled above, the base dilated into a sheath, 

 crowned with a membranous stipule, and is smooth or scattered over 

 with glands, or woolly, and the margin with a few short ciliated hairs, 

 the under side of the leaf has a stout mid-rib and branched lateral 

 veins, paler than the upper side, smooth, and studded over with small 

 glands, or more or less clothed with a soft pale wooUiness, as is the 

 upper side also, and the margin is smooth or rough, with short close 

 pressed bristles; sometimes the upper side is marked with a dark lunate 

 spot. Inflorescence terminating the stem and branches in erect oblong 

 crowded cylindrical spikes of either greenish or reddish flowers, the 

 peduncles and mostly the perianth rough, with small globose glands. 

 Perianth cut into five oblong segments, veiny. Stamens six, shorter 

 than the perianth, with simple /Zajnents and small ovate anthers. 



