Spikelets of 3 or 4 two-ranked scales, 1–1½-flowered; the 2 lower scales minute and empty, as in Cyperus, § 4, but style oftener 2-cleft and achene lenticular; spikes densely aggregated in solitary or triple sessile heads.—Culms leafy at base; involucre 3-leaved. (Named after Peter Kylling, a Danish botanist of the 17th century.)
1. K. pùmila, Michx. Annual; culms 2–9´ high; head globular or 3-lobed, whitish-green (about 4´´ broad), spikelets strictly 1-flowered; upper scales ovate, pointed, rough on the keel; stamens and styles 2; leaves linear.—Low grounds, Ohio to Ill., south to Fla. and Tex. Aug.
3. DULÍCHIUM, Pers. ([Pl. 1.])
Spikelets many- (6–10-) flowered, linear, flattened, sessile in 2 ranks on axillary solitary peduncles emerging from the sheaths of the leaves; scales 2-ranked, lanceolate, decurrent, forming flat wing-like margins on the joint below. Perianth of 6–9 downwardly barbed bristles. Stamens 3. Style 2-cleft above. Achene flattened, linear-oblong, beaked with the long persistent style.—A perennial herb, with a terete simple hollow culm (1–2° high), jointed and leafy to the summit; leaves short and flat, linear, 3-ranked. (An alteration of Dulcichinum, an old name for a species of Cyperus.)
1. D. spathàceum, Pers.—Borders of ponds, N. Scotia to Fla., west to Minn. and Tex. July–Sept.
4. ELEÓCHARIS, R. Br. Spike-Rush. ([Pl. 3.])
Spikelet single, terminating the naked culm, many–several-flowered. Scales imbricated all round in many (rarely in 2 or 3) ranks. Perianth of 3–12 (commonly 6) bristles, usually rough or barbed downward, rarely obsolete. Stamens 2–3. Style 2–3-cleft, its bulbous base persistent as a tubercle jointed upon the apex of the lenticular or triangular achene.—Leafless, chiefly perennial, with tufted culms sheathed at the base, from matted or creeping root-stocks; flowering in summer. (Name from ἕλος, a marsh, and χαίρω to delight in; being marsh plants.)
§ 1. Spikelet terete, hardly if at all thicker than the spongy-cellular culm; scales firmly persistent; style mostly 3-cleft; bristles 6 (rarely 7), firm or rigid, mostly barbed downward, equalling or surpassing the triangular or lenticular achene.
[*] Spikelet linear or lanceolate-awl-shaped, few-flowered; scales (only 3–9) few-ranked, convolute-clasping the long flattened joints of the axis, lanceolate, herbaceous (green) and several-nerved on the back, and with thin scarious margins.
1. E. Robbínsii, Oakes. Flower-bearing culms exactly triangular, rather stout, erect (8´–2° high), also producing tufts of capillary abortive stems or fine leaves, which float in the water; sheath obliquely truncate; spikelet 4–10´´ long; achene oblong-obovate, triangular, minutely reticulated, about half the length of the bristles, tipped with a flattened awl-shaped tubercle.—Shallow water, N. Eng. to Fla.