256 CYPERACEAE. 
22. Eleocharis rostellata Torr. Beaked Spike-rush. (Fig. 598.) 
Scirpus rostellatus Torr. Ann. Lyc. N. Y.3: 318. 1836. 
Eleocharis rostellata Torr. Fl. N. 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, 
1°-5° long. Upper sheath truncate; spikelet 
oblong, narrowed at both ends, thicker than 
the culm, t10-20-flowered, 3//-6’’ long, about 
1’ 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. Alsoin Cuba. Aug.— 
Sept. 
Be DICHROMENA Michx. Fl. Bor. Am. 1: 37. Gloo3 
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. 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 Dichromena. 
(Fig. 599.) 
Schoenus coloratus I,. Sp. Pl. 43. 1753- 
Dichromena leucocephala Michx. F1. Bor. Am. 
I: 37. 1803. 
Dichromena colorata A. S. Hitche. Ann. Rep. 
Mo. Bot. Gard. 4: 141. 1893. 
Glabrous, culm slender, erect, rather 
sharply triangular, 1°-2° tall. Leaves dis- 
tant, narrowly linear, about 1’ wide, much 
shorter than the culm, those of the involucre 
4-6, reflexed when mature, yellowish white 
at the base; head globose, 6//—10’’ 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-barréns of New 
Jersey to Florida and Texas. Also in tropical 
America, June-Sept. 
