20 >rEWOIRS FKOM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 



KEY TO THE SPECIES. 



Kootstock elongated ; radical leaves acuminate at the base ; racemes oblong, 



never producing bulblets ; acliene smooth and shining. 1. Polygonum bistortoides. 



Kootstock 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. 



Herl)aceou8 and more or less fleshy or sufli-utescent plants, glabrous, pubescent or 

 scurfy, sometimes glaucous, perennial by a creeping or horizontal rootstock. Rootstock 

 more or less enlarged, fleshy or A\'oody, chaffy with modified ocreae. Stem mostly erect, 

 becoming ^\'oody below, stout or slender, strict or flexuous, simple or branched from the 

 rootstock or throughout. Lea\'es cauline, fleshy, sometimes becoming coriaceous or thin. 

 (;)creae 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 di^-isions ending in racemes. Racemes many-flowered 

 but loose and open, naked or leafy. Ocreolae 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. 3. P. alpinum. 



Leaves ovate; panicles nearly simple ; achene ovoid. 4. P. phytolaccaefolium. 



Inflorescence consisting of axillary clusters and racemes. 



Leaves more or less petioled, usually pubescent or scurfy ; achene ob- 

 ovoid. 5. p. Newberryi. 

 Leaves sessile, nearly' glabrous, glaucous; acliene ovoid. 6. P. Davisiae. 



3. SUBGENUS PERSICARIA. 



Herbaceous or suftrutesceut, terrestrial or aquatic, annual or perennial plants, be- 

 coming more or less woody at the base or throughout, glabrous, pubescent or glandular. 

 Stems erect (jr prostrate and creeping, sometimes floating, simple or variously branched, 

 more or less channeled, never twining nor climbing. Leaves cauhne, entire or somewhat 



