CYPEBACE^. (sedge FAMILY.) 557 



15. CHiETOSPORA, E. Br. 



Spikes few- (1 -8-) flowered. Scales imbricated in two rows; the lower 

 ones empty, the npper bearing perfect flowers. Perianth of 3-6 scalirous or 

 plumose bristles. Stamens 3. Style 3-clett, not dilated at the base, nearly 

 deciduous. Nut triangular, mostly pointed by tlie persistent base of the style. 

 — Leaves radical, narrow. Spikes in a terminal cluster, subtended by a 1 - 2- 

 leaved involucre. 



1. C. nigricans, Kunth. Culms tufted, jointed near the summit ; 

 leaves rigid, erect, semi-terete, shorter than the culms; sheatlis black; in- 

 volucre 2-leaved, the lower longer than the ovoid dark brown head ; spikes 

 ovate-lanceolate, compressed, 6 - 8-flowered ; scales ovate, keeled ; rachis zig- 

 zag ; bristles 6, unequal, dilated at the base, hispid upward, longer than the 

 globose-3-angled white and polished nut. (Schoenus nigricans, L.) — Damp 

 soil, chiefly along the coast, Florida. May. % — Culms 1°- H° high. 



16. PSILOCARYA, Torr. 



Spikes many-flowered, terete. Scales imbricated in several rows, mem- 

 branaceous, all bearing perfect flowers. Perianth none. Stamens 2. Style 

 2-cleft Nut biconvex, transversely wrinkled, crowned with the persistent 

 base of the style. — Culms leafy. Spikes ovate, disposed in spreading lateral 

 and terminal corymbs. 



1. P. rhynchosporoides, Torr. Culms nearly terete (i°-2°high); 

 leaves narrowly linear, longer than the culm; corymbs 2-3, widely spread- 

 ing, the terminal one mostly compound ; spikes pedicelled ; scales ovate, 

 acute ; nut orbicular, strongly wrinkled ; tubercle compressed, very short, ses- 

 sile, but not decurrent on the edges of the nut. (Scirpus nitens, Vahl.) — 

 Shallow pine barren ponds, Florida to North Carolina. July. (T) — Culms 

 commonly rooting at the lower joints. 



2. P. COrymbiformis, Benth. Corymbs less spreading : scales of the 

 spikelets tliinner and narrower, obtuse ; nut faintly wrinkled ; tubercle tri- 

 angular, acuminate, as long as tlie nut ; otherwise like tlie preceding. — 

 Georgia, Florida, and westward. 



17. DICHROMENA, Eichard. 



Spikes compressed, few-flowered, aggregated in a terminal head, and sur- 

 rounded by an involucre of several leaves, which are commonly white at the 

 base. Scales imbricated in two rows, most of them bearing abortive flowers. 

 Stamens 3. Style 2-cleft. Nut lenticular, crowned with the broad and per- 

 si.stent base of the style. Perianth none. Perennials. Culms jointless, leafy 

 at the base. Scales white, membranaceous. 



1. D. leucocephala, Michx. Culms (10-U°high) slender, 3-angIed ; 

 leaves narrowly linear; involucre of 4-7 narrow leaves; nut orbicular, 

 wrinkled ; tubercle flat, broadly conical, sessile, but not decurrent. — Damp 

 soil, Florida to North Carolina. August- Sept, — Involucre unchauged in 

 drying. 



