20) MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 
KEY TO THE SPECIES. 
Rootstock elongated; radical leaves acuminate at the base; racemes oblong, 
never producing bulblets; achene smooth and shining. 1. POLYGONUM BISTORTOIDES. 
Rootstock bulb-like; radical leaves usually cordate or subcordate ; racemes 
narrowly cylindric, producing bulblets at the base; achene granular 
and dull. 2. PoLYGONUM VIVIPARUM. 
2. SUBGENUS ACONOGONON. 
Herbaceous and more or less fleshy or suffrutescent plants, glabrous, pubescent or 
scurfy, sometimes glaucous, perennial by a creeping or horizontal rootstock. — Rootstock 
more or less enlarged, fleshy or woody, chaffy with modified ocreae. Stem mostly erect, 
becoming woody below, stout or slender, strict or flexuous, simple or branched from the 
rootstock or throughout. Leaves cauline, fleshy, sometimes becoming coriaceous or thin, 
Ocreae funnelform, two-cleft, somewhat oblique, membranous, hyaline, thin, brittle, glab- 
rous or pubescent. Inflorescence axillary and terminal, racemose or paniculate, more 
or less compound, the ultimate divisions ending in racemes. Racemes many-flowered 
but loose and open, naked or leafy. Qcreolae funnelform, oblique and shallow. — Pedi- 
cels articulated at the base of the calyx. Calyx colored, five-parted, never glandular- 
punctate nor much enlarged in fruit. Stamens eight, included. Style three-parted. 
more or less exserted. Stigmas capitate. Achene triquetrous, brownish or greenish, 
nearly smooth, at length protruding slightly beyond the calyx. Albumen horny. 
Cotyledons accumbent. 
KEY TO THE SPECIES. 
Inflorescence consisting of axillary and terminal racemes or panicled racemes. 
Leaves lanceolate; panicles compound and dense; achene obovoid. P. ALPINUM. 
Leaves ovate; panicles nearly simple; achene ovoid. 4. P. PHYTOLACCAEFOLIUM. 
Inflorescence consisting of axillary clusters and racemes. 
oo 
Leaves more or less petioled, usually pubescent or scurfy ; achene ob- 
ovoid. P. NEWBERRY!I. 
Leayes sessile, nearly glabrous, glaucous; achene ovoid. 6. P. DAVISIAE. 
or 
3. SUBGENUS PERSICARIA. 
Herbaceous or suffrutescent, terrestrial or aquatic, annual or perennial plants, be- 
coming more or less woody at the base or throughout, glabrous, pubescent or glandular. 
Stems erect or prostrate and creeping, sometimes floating, simple or variously branched, 
more or less channeled, never twining nor climbing. Leaves cauline, entire or somewhat 
