530 CYPERACEJE. (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. scrRPOIDES, Torr., 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 (19-119 high) slender, 3-angled ; 
leaves wly 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 (29 — 39 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-cleft, the divisions often 2 - 3-cleft, de- 
ciduous. Nut globose-ovate, the pericarp thickened and corky near the apex. 
Tuberclegione. — 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 sma", 
3-4 in a cluster, deep brown; scales about 6, the uppermost bearing à perfect 
flower, the next below staminiferous, the others empty; nut ovate, pom 
wrinkled. (Schænus effusus, Swartz.) — Fresh or brackish marshes along the 
coast, Florida to North Carolina, and westward. July and Ahg. 
Jose. 20. SCLERIA, L. Nor-Rusn. 
. Flowers monocious. Sterile spike few -many-flowered. Scales cpi 
.  bricated in 2-8 rows. Fertile flowers solitary, separate or at the base € 
_ Sterile spike. Stamens 1-3. Style 3-cleft. Nut globose or ovate, Stony *" 
