30 CYPERACEAE. 



7. STENOPHYLLUS Eaf. Scapose tufted herbs. Leaves basal: blades 

 narrowly linear, filiform or setaceous, the sheaths ciliate or pubescent. Spike- 

 lets umbellate, capitate, or solitary, the scales spiral, niostlj- deciduous. 

 Involucre of 1-several bracts. Flowers perfect. Perianth none. Style gla- 

 brous, the base much swollen and persistent as a tubercle on the achene. 



Leaf-blades eciliate : achenes about 1 mm. long. 1. S. coarctatua. 



Leaf-blades ciliate : achenes about 0.5 mm. long. 2. S. Carteri. 



1. S. coarctatus (Ell.) Britton. Scapes 2-3 dm. tall, smooth: umbel con- 

 tracted: spikelets linear-oblong, 10-15-flowered: achenes obovoid, about 1 mm. 

 long. — Pinelands. 



2. S. Carteri Britton. Scapes 1-1.5 dm. tall, scabrous near the top: umbel 

 not contracted : spikelets ovoid or nearly so, few-flowered : achenes broadly 

 obovoid, about 0.5 mm. long. — Pinelands. 



8. DICHROMENA Michx. Caulescent herbs with the spikelets crowded 

 in a terminal head involucrate by several bracts, which are often white at the 

 base. Spikelets compressed, several-many-flowered. Scales spirally imbri- 

 cate all around, several of them with imperfect flowers, or empty. Perianth 

 none. Style subulate. Achene lenticular, transversely rugose, crowned with 

 the broad persistent base of the style (tubercle). — White-top. 



Bracts of the involucre 4-6, linear : tubercle truncate on top of the achene. 



Leaves filiform above the dilated base : achenes dark ; tubercle low, blunt. 



1. D. fforidensis. 

 Leaves linear above the dilated base: achenes pale; tubercle 



long, acute. 2. D. colorata. 



Bracts of the involucre 7-10, lanceolate : tubercle decurrent on the 



sides of the achene. 3. D. latifoUa. 



1. D. floridensls Britton. Stems copiously tufted, 2-4 dm. tall, slender: leaf- 

 blades involute-filiform: bracts of the involucre attenuate: heads about 1 cm. 

 in diameter: spikelets oblong: scales pale: achene-body obovoid, slightly over 

 1 mm. long, dark-brown, finely wrinkled. — Pinelands. 



2. D. colorata (L.) A. Hitchc. Stem slender, rather sharply triangular, 3-6 

 dm. tall: leaf -blades narrowly linear, much shorter than the stem: bracts of 

 the involucre reflexed when mature, yellowish-white at the base: head globose, 

 1-2 cm, in diameter: spikelets narrowly oblong, acute: scales membranous, 

 lanceolate, nearly white, subacute: achene-body obovoid, a little over 1 mm, 

 long, pale-brown, compressed. — Everglades and low pinelands. — F, K, (Ber., 

 Bah., Cuha, Ant.) 



3. D, latifolia Baldw, Similar to No. 2, but stem stouter, obtusely triangular 

 or nearly terete: leaf-blades lanceolate or linear-lanceolate, tapering gradually 

 to a long acuminate apex from a broad base, 3-8 mm, wide, sometimes over- 

 topping the stem: bracts of the involucre strongly reflexed when old: head 

 globose, 1-2 cm, in diameter: spikelets oblong, subacute: scales ovate-lanceo- 

 late, nearly white, rather obtuse: achene-body nearly orbicular in outline, a 

 little over 1 mm. long, pale-brown, faintly wrinkled transversely and longi- 

 tudinally so as to appear reticulated. — Everglades. 



9. SCHOENUS L. Acaulescent rush-like herbs. Leaf-sheaths dark-col- 

 ored; blades resembling the scapes, half -terete. Spikes in a terminal cluster, 

 1-8-flowered, subtended by an involucre of 1-2 bracts. Spikelets crowded, 

 often dark-colored: scales imbricate in 2 rows, per.sistent. Perianth of 3-6 

 scabrous or plumose bristles. Styles barely enlarged at the base, almost 

 wholly deciduous. Achene 3-angled, smooth. 



