CYPERACE^E. (SEDGE FAMILY.) 567 



§ 2. TRICHELOSTYLIS, Lcstib. Style 3-cle/l and the achenium triangular: 

 other/rise nearly as in § 1 : the spikes small and fewer-flowered. 



3. P. autumn&lis, Roern. & Schult. Annual (3'- 16' high), in tufts; 

 culms flat, slender, diftus» or erect ; leaves flat, acute ; umbel compound ; spikes 

 Oblong, acute (l"-2" long), single or 2-3 in a cluster; the scales ovate-lanceo- 

 late, mucronate; stamens 1-3. (Scirpus autumnalis, L.) — Low grounds, 

 Maine to Illinois, and southward. Aug. - Oct. 



§ 3. ONCOSTYLIS, Martius. Style 3-clrfl, slender, its thichish base more tardily 

 deciduous from the apex of the triangular achenium. 



4. F. capillciris, Gray. Low annual, densely tufted (3' -9' high) ; culm 

 and leaves nearly capillary, the latter short ; umbel compound or panicled ; 

 spikes (2" long) ovoid-oblong; stamens 2 ; achenium minutely wrinkled, very 

 obtuse. (Scirpus capillaris, L.) — Sandy fields : common. Aug., Sept. 



(F. congesta, Torr., a diminutive Southern species, with the 2-cleft style 

 not ciliate, has been detected in ballast-sand at Camden, New Jersey, opposite 

 Philadelphia, by C. F. Parker : probably only a waif.) * 



11. DICHEOMENA, Richard. Dichromena. (PI. 4.) 



Spikes aggregated in a terminal leafy-involucrate head, more or less com- 

 pressed, few-flowered, all but 3 or 4 of the flowers usually imperfect or abortive. 

 Scales imbricated somewhat in 2 ranks, more or less conduplicate or boat- 

 shaped, keeled, white or whitish. Stamens 3. Style 2-cleft. Perianth, bristles, 

 &c, none. Achenium lenticular, wrinkled transversely, crowned with the per- 

 sistent and broad tubercled base of the style. — Culms leafy, from creeping 

 perennial rootstocks ; the leaves of the involucre mostly white at the base 

 (whence the name, from fit's, double, and xpmpa, color). — Differs (too little) 

 from the next genus in the involucrate bracts and flattened spikes. 



1. D. leucocephala, Michx. Culm triangular (l°-2° high); leaves 

 narrow ; those of the involucre 4 - 7 ; achenium truncate, not margined. — 

 Damp pine barrens of New Jersey to Virginia and southward. Aug., Sept. 



2. D. Iatif61ia, Baldwin. Culm stouter, nearly terete; leaves broadly 

 linear, those of the involucre 8-9, tapering from base to apex ; achenium 

 round-obovate, faintly wrinkled, the tubercle decurrent on its edges. — S. Vir- 

 ginia ? and southward. 



12. EHYNCHOSPORA, Vahl. Beak-Rush. (PI. 4.) 



Spikes panicled or variously clustered, ovate, globular, or spindle-shaped, 

 terete, or sometimes flattish ; but the scales open or barely concave (not boat- 

 shaped nor keeled) ; the lower ones commonly loosely imbricated and empty, 

 the uppermost often subtending imperfect flowers. Perianth in the form of 

 (mostly 6) bristles, or occasionally wanting. Achenium lenticular, globular, 

 or flat, crowned with a conspicuous tubercle or beak consisting of the persistent 

 and indurated base or even of the greater part of the style. — Chiefly peren- 

 nials, with more or less triangular and leafy culms ; the spikes in terminal and 

 axillary clusters : flowering in summer. (Name composed of pvyxos, a snout, 

 and anopd, a seed, from the beaked achenium.) 



