256 CYPERACEAE. 



22. Eleocharis rostellata Torr. Beaked Spike-rush. (Fig. 598.) 



Scirpus roslellatusforr. Ann. Lye. X. Y. 3: 318. 1836. 

 Eleocharis roslellata Torr. Fl. X. Y. 2: 347. 1843. 



Perennial by a short caudex, culms slender, 

 wiry, the fertile erect or ascending, the sterile 

 reclining and rooting at the summit, grooved, 

 i-5 long. Upper sheath truncate; spikelet 

 oblong, narrowed at both ends, thicker than 

 the culm, io-2o-flowered, 3 // -6 // long, about 

 i" in diameter; scales ovate, obtuse or the 

 upper acute, green with a somewhat darker mid- 

 vein, their margins slightly scarious; 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 re- 

 ticulated; tubercle conic-subulate, about one-half 

 as long as the achene or shorter, capping its sum- 

 mit, partly or entirely falling away at maturity. 



In marshes and wet meadows, Vermont and western 

 New York to British Columbia, south to Florida, 

 Texas, Mexico and California. Also in Cuba. Aug.- 

 Sept. 





5. DICHROMENA Michx. Fl. Bor. Am. i: 37. 1803. 



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-flowered. Scales spirally imbricated all around, several of them with imper- 

 fect 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 southwest- 

 ern United States. 



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



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



2. D. latifolia. 



i. Dichromena colorata (L,.) A. S. Hitchcock. 



(Fig. 599.) 



Schocnus coloratus L. Sp. PI. 43. 1753. 



Dichromena leucocephala Michx. Fl. Bor. Am. 

 i: 37. 1803. 



Dichromena colorata A. S. Hitchc. Ann. Rep. 

 Mo. Bot. Card. 4: 141. 1893. 



Glabrous, culm slender, erect, rather 

 sharply triangular, i-2 tall. Leaves dis- 

 tant, narrowly linear, about \" wide, much 

 shorter than the culm, those of the involucre 

 4-6, reflexed when mature, yellowish white 

 at the base; head globose, 6 // -io" in diame- 

 ter; spikelets narrowly oblong, acute; scales 

 membranous, lanceolate, nearly white, i- 

 nerved, subacute at the apex; achene ob- 

 ovate, brown, papillose or wrinkled trans- 

 versely, nearly truncate at the summit, com- 

 pressed, covered by the tubercle which is not 

 decurrent on its edges. 



In moist sandy soil, pine -barrens of New 

 Jersey to Florida and Texas. Also in tropical 

 America. June-Sept. 



Narrow-leaved Dichromena. 



