MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 23 



5. SUBGENUS TOVARA. 



Annual herbaceous plants becoming somewhat woody below. Stem mostly erect, 

 virgate, simple or virgately branched, somewhat channeled. Leaves membranous, short- 

 petioled, acute at both ends. Ocreae cylindric, fringed with bristles. Inflorescence 

 axillary and terminal, consisting of spicate racemes. Racemes linear, very long and 

 wand-like, conspicuously interrupted. Calyx more or less colored, somewhat recurved, 

 four-parted, the segments unequal. Stamens five, included. Style two-parted, conspicu- 

 ously exserted, the segments recurved or curled. Achene lenticular, strongly biconvex, 

 brown or cream-colored, smooth and shining. Albumen horny. Cotyledons accumbent. 



One species. 33. P. Virginianum. 



6. SUBGENUS AVICULARIA. 



Herbaceous, suflfrutescent or suflFruticose plants, annual or perennial by a woody 

 rootstock, glabrous, more or less scurfy, often glaucescent or glaucous. Stem erect, 

 ascending or prostrate, virgate, slender or stout, more or less ridged, simple or variously 

 branched, either from the base or above or throughout. Leaves cauline only, rather 

 coriaceous or somewhat fleshy, variously nerved, flat or revolute, sometimes with two 

 lateral impressions parallel with and on either side of the midrib, more or less conspicu- 

 ously articulated to the ocreae, often reduced to bracts towards the ends of the branches. 

 Ocreae funnelform, more or less oblique, two-parted when young, at length lacerate, 

 hyaline, never fringed, more or less nerved. Inflorescence axillary, consisting of clusters 

 bearing normally several flowers at each node throughout the plant or confined to the 

 branches and branchlets, forming thus terminal, either interrupted or continuous spicate 

 racemes. Calyx five-parted, rarely six-parted, mostly green with white, pink or rose- 

 colored margins, occasionally colored. Stamens varying from three to eight, often five 

 or six, included. Style three-cleft or three-parted, included or exserted at maturity, 

 sometimes almost wanting and the stigma nearly sessile. Achene triquetrous, included 

 or slightly exserted, brown or black, granular or smooth and shining. Albumen horny. 

 Cotyledons incumbent. 



KEY TO THE SPECIES. 



Perennial by large, woody, creeping rootstocks. 



Inflorescence crowded at the ends of branches ; ocreae conspicuously 



lacerate ; achene black. 34. P. Paronychia. 



Inflorescence not crowded at the ends of the branches ; ocreae inconspi- 

 cuous, lacerate; achene chestnut-colored. 35. P. Shastense. 



