530 CYPEEACE^E. (SEDGE FAMILY.; 



orbicular, strongly wrinkled ; tubercle compressed, very short, sessile, but not 

 decurrent on the edges of the nut. (Scirpus nitens, Vahl.) Shallow pine- 

 barren ponds, Florida to North Carolina. July. Culms commonly root- 

 ing at the lower joints. 



P. SCIRI-OIDES, Ton-., if within our limits, may be known by its nearly smooth 

 nut, and slender beak-like decurrent tubercle. 



18. DICHROMENA, Richard. 



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 few rows, most of them bearing abortive flowers. 

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

 ent base of the style. Perianth none. Perennials. Culms jointless, leafy at 

 the base. Scales white, membranaceous. 



1. D. leucocephala, Michx. Culms (l-l high) slender, 3-angled ; 

 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. Aug. and Sept. Involucre unchanged in drying. 



2. D. latifolia, Baldw. Culms stout (2 -3 high), nearly terete; leaves 

 broadly linear, elongated ; leaves of the involucre 8-9, tapering from the broad 

 (3"- 4" wide) base to the slender summit, becoming reddish ; nut round-obovate, 

 faintly wrinkled ; tubercle flat, conical, obtuse, the sides decurrent on the edges 

 of the nut. Low pine barrens, Florida to North Carolina. May July. 

 Heads larger than those of the preceding. 



19. CLADIUM, Browne. 



Spikes ovate, 1 - 2-flowered. Scales loosely imbricated, the lower ones empty. 

 Perianth none. Stamens 2. Style 2-3-clcft, the divisions often 2-3-cleft, de- 

 ciduous. Nut globose-ovate, the pericarp thickened and corky near the apex. 

 Tubercle none. Culms tall. Spikes disposed in axillary and terminal cyme- 

 like panicles. 



1. C. effusum, Torr. (SAW-GRASS.) Culms (4- 8 high) nearly terete ; 

 leaves linear, elongated, saw-edged ; panicles numerous, diffuse ; spikes small, 

 3-4 in a cluster, deep brown ; scales about 6, the uppermost bearing a perfect 

 flower, the next below staminiferous, the others empty ; nut ovate, pointed, 

 wrinkled. (Schoenus effusus, Swartz.) Fresh or brackish marshes along the 

 coast, Florida to North Carolina, and westward. July and Aug. 



20. SCLERIA, L. NUT RUSH. 



Flowers monoecious. Sterile spike few - many-flowered. Scales loosely im- 

 bricated in 2 - 3 rows. Fertile flowers solitary, separate or at the base of the 

 sterile spike. Stamens 1 - 3. Style 3-cleft. Nut globose or ovate, stony or 

 bony. Chiefly perennials, with creeping rootstocks, and triangular leafy culms 

 Spikes clustered, lateral and terminal. 



