CYPERACE^E. (SEDGE FAMILY.) 57? 



5. DICHROMENA, Richard. (PI. 4.) 



Spikelets aggregated in a terminal leafy-involucrate head, more or less com- 

 pressed, few-flowered, all but 3 or 4 of the flowers usually imperfect or abor- 

 tive. Scales imbricated somewhat in 2 ranks, more or less conduplicate or 

 boat-shaped, keeled, white or whitish. Stamens 3. Style 2-cleft. Perianth, 

 bristles, etc., none. Achene lenticular, wrinkled transversely, crowned with 

 the persistent and broad tubercled base of the style. Culms leafy, from creep- 

 ing perennial rootstocks ; the leaves of the involucre mostly white at the base 

 (whence the name, from Sis, double, and xp&>A*> color). 



1. D. leucocephala, Michx. Culm triangular (1-2 high); leaves 

 narrow ; those of the involucre 4 - 7 ; achene truncate, not margined. Damp 

 pine-barrens, N. J. to Fla. Aug., Sept. 



2. D. latifblia, Baldwin. (PI. 4, fig. 1 - 5.) Culm stouter, nearly te- 

 rete ; leaves broadly linear, those of the involucre 8 or 9, tapering from base to 

 apex ; achene round-obovate, faintly wrinkled, the tubercle decurrent on its 

 edges. Low pine-barrens, Va. to Fla. 



6. PSILOCARYA, Torr. BALD-RUSH. (PI. 4.) 



Spikelets ovoid, terete, the numerous scales all alike and regularly imbri- 

 cated, each with a perfect flower. Perianth (bristles) wholly wanting. Sta- 

 mens mostly 2. Style 2-cleft, its base or the greater part of it enlarging and 

 hardening to form the beak of the lenticular or tumid more or less wrinkled 

 achene. Annuals, with leafy culms, the spikelets in terminal and axillary 

 cymes. (Name from tyi\6s, naked, and itapva, nut.) 



1. P. SCirpoides, Torr. Annual (4 -10' high), leafy; leaves flat; spike- 

 lets 20 - 30-flowered ; scales oblong-ovate, acute, chestnut-colored ; achene 

 somewhat margined, beaked with a sword-shaped almost wholly persistent 

 style. (Rhynchospora scirpoides, Gray.) Inundated places, S. N. Eng. 



7. FIMBRISTYLIS, Vahl. (PI. 3.) 



Spikelets several - many-flowered, terete; scales all floriferous, regularly 

 imbricated in several ranks. Perianth (bristles, etc.) none. Stamens 1-3. 

 Style 2 - 3-cleft, often with a dilated or tumid base, which is deciduous (except 

 in n. 4) from the apex of the naked lenticular or triangular achene. Other- 

 wise as in Scirpus. Culms leafy at base. Spikelets in our species umbelled, 

 and the involucre 2-3-leaved. (Name compounded of Jimbrfa, a fringe, and 

 stylus, style, which is fringed with hairs in the genuine species.) 

 * Style 2-cleft, flattened and ciliate; achene lenticular ; tubercle soon deciduous ; 

 spikelets many -flowered. 



1. F. spadicea, Vahl, var. castanea, Gray. Culms (i-2 high) 



tufted from a perennial root, rigid, as are the thread-form convolute-channelled 

 leaves, smooth; spikelets ovate-oblong becoming cylindrical, dark chestnut- 

 color (2" thick) ; stamens 2 or 3 ; achene very minutely striate and reticulated. 

 Salt marshes along the coast, N. Y. and N. J. to Fla. July- Sept. Scales 

 lighter colored than in the tropical form. 



2. F. laxa, Vahl. (PL 3, fig. 1 - 5.) Culms slender (2-12' high} from 

 an annual root, weak, grooved and flattish : leaves linear,, flat, ciliate-denticulatc, 



