11. HEMICÁRPHA, Nees. ([Pl. 2.])
Spikelet, flowers, etc., as in Scirpus, except that there is a minute translucent scale (readily overlooked) between the flower and the axis of the spikelet. Stamen only one. Style 2-cleft. Bristles or other perianth none. (Name from ἥμι, half, and κάρφος, straw or chaff, in allusion to the single inner scalelet.)
1. H. subsquarròsa, Nees. Dwarf or minute annual (1–5´ high); involucre 1-leaved, as if a continuation of the bristle-like culm, and usually with another minute leaf; spikelets 2–3 (barely 2´´ long); scales brown, tipped with a short recurved point.—Sandy borders of ponds and rivers, N. Eng. to Fla., west to the Pacific.
12. LIPOCÁRPHA, R. Br. ([Pl. 2.])
Spikelets terete, many-flowered, in a terminal close cluster involucrate by leafy bracts. Scales spatulate, regularly imbricated all round in many ranks, awnless, deciduous, a few of the lowest empty. Inner scales (bractlets) 2 to each flower, thin, one between the scale of the spikelet and the flower, one between the latter and the axis of the spikelet. Bristles or other perianth none. Stamens 1 or 2. Style 2–3-cleft. Achene flattish or triangular, naked at the tip.—Culms leafy at base. (Name formed of λίπος, fat, and κάρφος, chaff, from the thickness of the inner scales of some species.)
1. L. maculàta, Torr. Annual; culm (4–8´ high) much longer than the linear concave leaves; spikelets (1–2´´ long) green and dark-spotted; inner scales delicate; stamen one; achene oblong with a contracted base.—Springy or miry places, Va. to Fla.; near Philadelphia, probably adventive.
13. RHYNCHÓSPORA, Vahl. Beak-Rush. ([Pl. 4.])
Spikelets panicled or variously clustered, ovate, globular, or spindle-shaped, terete, or sometimes flattish; but the scales open or barely concave (not boat-shaped nor keeled); the lower commonly loosely imbricated and empty, the uppermost often subtending imperfect flowers. Perianth in the form of bristles (mostly 6). Stamens mostly 3. Achene lenticular, globular, or flat, crowned with a conspicuous tubercle or beak consisting of the persistent indurated base or even of the greater part of the style.—Chiefly perennials, with more or less triangular and leafy culms; the spikelets in terminal and axillary clusters; flowering in summer. (Name composed of ῥύγχος, a snout, and σπορά, a seed, from the beaked achene.)
§ 1. RHYNCHOSPORA proper. Spikelets terete or biconvex, few–many-flowered; style conspicuously 2-cleft, its base only forming the tubercle of the mostly lenticular achene; bristles usually present, merely rough or barbed-denticulate (not plumose).
[*] Achene transversely wrinkled; bristles mostly 6, upwardly denticulate.