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 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 20 species, natives of America. Besides the following, 2 others occur in the southwestern United States. Type species: Dichromena leucocephala Michx.

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.) Hitchcock. Narrow-Leaved Dichromena

Fig. 839

Schoenus coloratus L. Sp. PI. 43. 1753' D. leucocephala Michx. Fl. Bor. Am. 1: 37. 1803. Dichromena colorata A. S. Hitchc. Ann. Rep. Mo. Bot. Gard. 4: 141. 1893.

Glabrous, culm slender, erect, rather sharply triangular, 1°-2° tall. Leaves distant, narrowly linear, about 1" wide, much shorter than the culm, those of the involucre 4-6, rerlexed when mature, yellowish-white at the base; head globose, 6"-10" in diameter; spikelets narrowly oblong, acute; scales membranous, lanceolate, nearly white, i-nerved, subacute at the apex; achene obovate, brown, papillose or wrinkled transversely, nearly truncate at the summit, compressed, covered by the truncate-based tubercle.

In moist sandy soil, New Jersey to Florida and Texas. Bermuda; tropical America. June-Sept

1 Dichromena Colorata L Hitchcock Narrow Leaved Di 8391 Dichromena Colorata L Hitchcock Narrow Leaved Di 840

2. Dichromena Latifolia Baldw. Broad-Leaved Dichromena

Fig. 840

Dichromena latifolia Baldw.; Ell. Bot. S. C. & Ga. 1: 90. 1816.

Culm stout, obtusely triangular or nearly terete, the leaves lanceolate or linear-lanceolate, tapering gradually to a long-acuminate apex from a broad base, 1 1/2"-4" wide, sometimes overtopping the culm, but the lowest much shorter, those of the involucre 7-10, strongly reflexed when old. Head globose, 6"-9' in diameter; spikelets oblong, subacute; scales ovate-lanceolate, nearly white, rather obtuse; achene nearly orbicular in outline, pale brown, faintly wrinkled transversely and longitudinally, so as to appear reticulated; tubercle decurrent on the margins of the achene.

In wet pine barrens, Virginia to Florida and Texas. June-Aug.