172 FLORA. 



10-20-flowered, 6-12 mm. long, about 2 mm. in diameter; scales ovate, obtuse or 

 the upper acute, green with a somewhat darker midvein; bristles 4-8, retrorsely 

 barbed, longer than the achene and tubercle; stamens 3; style 3-cleft; achene 

 oblong-obovoid, obtusely 3 -angled, its surface finely reticulated; tubercle conic- 

 subulate, about one-half as long as the achene or shorter, capping its summit, 

 partly or entirely falling away at maturity. In marshes and wet meadows, N. H. 

 to Vt. and W. N. Y., Br. Col., Fla., Tex., Mex. and Cal. Also in Cuba. Aug-Sept. 



5. DICHROMENA Michx. 



Leafy-stemmed sedges, perennial by rootstocks, the spikelets crowded in a 

 terminal head involucrate by the upper leaves, which are often white at the base. 

 Spikelets compressed, several-many-fiowered. Scales spirally imbricated all 

 around, several of them with imperfect flowers, or empty. Perianth none. Stamens 

 3. Style 2-cleft, its branches subulate. Achene lenticular, transversely rugose, 

 crowned with the broad persistent base of the style (tubercle). [Greek, alluding to 

 the two-colored involucral leaves.] About 8 species, natives of America. Besides 

 the following, another occurs in the southwestern United States. 



Leaves of the involucre linear ; tubercle truncate at the base. 1. D. colorata. 



Leaves of the involucre lanceolate, long-acuminate ; tubercle decurrent on the edges of 



the achene. 2. D. latifolia. 



1. Dichromena colorata (L.) A. S. Hitchcock. Narrow-leaved Dichro- 

 MENA. (I. F. f. 599.) Glabrous; culm slender, erect, rather sharply triangular, 

 0.3-0.6 m. tall. Leaves distant, narrowly linear, about 2 mm. wide, much 

 shorter than the culm, those of the involucre 4-6, reflexed when mature, yellowish 

 white at the base ; head globose, 1-2 cm. in diameter ; spikelets narrowly oblong, 

 acute; scales membranous, lanceolate, nearly white, i-nerved, subacute at the 

 apex ; achene obovate, brown, nearly truncate at the summit, compressed, covered 

 by the tubercle which is not decurrent on its edges. In moist sandy soil, pine 

 barrens of N. J. to Fla. and Tex. Also in tropical America. June-Sept. 



2. Dichromena latifolia Baldw. Broad-leaved Dichromena (I. F. f. 600.) 

 Similar to the preceding species but the culm stouter, obtusely triangular or nearly 

 terete, the leaves lanceolate or linear-lanceolate, tapering gradually to a long-acumi- 

 nate apex from a broad base, 3-8 mm. wide, sometimes overtopping the culm, but 

 the lowest much shorter, those of the involucre 7-10, strongly reflexed when old. 

 Head globose, 1-2 cm. in diameter; spikelets oblong, subacute; scales ovate- 1 

 lanceolate, nearly white, rather obtuse; achene nearly orbicular in outline, pale I 

 brown, faintly wrinkled transversely and longitudinally, so as to appear reticu- 

 lated ; the tubercle decurrent on its margins. In wet pine barrens, Va. to Fla. and j 

 Tex. June-Aug. 



6. PSILOCARYA Torr. 



Annual sedges, with fibrous roots, slender leafy stems and ovoid or oblong 

 many-flowered terete spikelets in terminal and axillary, mostly compound umbels 

 the rays and raylets bracted at the base. Scales of the spikelets spirally imbri- 

 cated all around, all fertile, deciduous. Flowers perfect. Perianth none. Stamens 

 1 or 2. Style 2-cleft, enlarged at the base. Achene lenticular or biconvex, smooth 

 or transversely wrinkled, capped by the persistent base of the style (tubercle), or 

 nearly the whole style persistent as a beak. [Greek, referring to the absence oi 

 perianth -bristles.] About 10 species, natives of temperate and tropical America. 

 Besides the following, another occurs in the southeastern United States. 

 Achene strongly wrinkled, much longer than the subacute tubercle 1. P. nit ens 



Achene smooth or but little wrinkled ; tubercle subulate. 2. P. scirpoides 



I. Psilocarya nitens (Vahl) Wood. Short-beaked Bald-rush. (I. F. f. 

 601.) Glabrous; culms tufted, slightly angled, 7-36 cm. tall. Leaves narrows 

 linear, about 2 mm wide, smooth, sometimes overtopping the culm, sheathing a 

 the base the midvein prominent; umbels mostly loose; spikelets ovoid; 4-6 mm 

 long, rather less than 2 mm. in diameter; scales brown, broadly ovate, thin 

 i-nerved, obtuse, acute or apiculate ; achene lenticular, nearly orbicular, ligh 

 brown, strongly wrinkled transversely; tubercle shorter than the achene, subacute 

 2-lobed at the base. In wet soil, L. I. and Del. to Fla. and Tex., near the coast 

 July-Oct 



