Part 184 (1/2)
-- 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._
1. R. cymsa, Nutt. _Culm triangular; leaves linear_ (' wide); cymes corymbose, the _spikelets crowded and cl.u.s.tered; achene round-obovate_, twice the length of the bristles, four times the length of the depressed-conical tubercle.--Low grounds, Penn. and N. J. to Fla., west to N. Ind. and Ill.
2. R. Torreyana, Gray. (Pl. 4, figs. 1--5.) _Culm nearly terete, slender; leaves bristle-form_; cymes panicled, somewhat loose, the _spikelets mostly pedicelled; achene oblong-obovate_, longer than the bristles, thrice the length of the broad compressed-conical tubercle.--Swamps; pine-barrens of N. J. to S. C.
3. R. inexpansa, Vahl. _Culm triangular_, slender; _leaves narrowly linear; spikelets spindle-shaped, mostly pedicelled, in drooping panicles; achene oblong_, half the length of the slender bristles, twice the length of the triangular-subulate tubercle.--Low grounds, Va. to Ga.
[*][*] _Achene smooth and even._
[+] _Bristles 6, long and conspicuous, upwardly denticulate._
4. R. fusca, Roem. & Schultes. Culm 6--12' high; _leaves bristle-form channelled_; spikelets ovate-oblong, few, cl.u.s.tered in 1--3 loose heads (dark chestnut-color); _achene obovate, half the length of the bristles_, equalling the triangular-sword-shaped acute tubercle, which is rough serrulate on the margins.--Low grounds, N. Brunswick to N. J., west to L. Superior. (Eu.)
5. R. gracilenta, Gray. Culms very slender, 1--2 high; _leaves narrowly linear_; spikelets ovoid, in 2--4 small cl.u.s.ters, the lateral long-peduncled; _achene ovoid, rather shorter than the bristles_, about the length of the flat awl-shaped tubercle.--Low grounds, southern N. Y.
and N. J. to Fla.
6. R. oligantha, Gray. Culm and leaves filiform, 6--12' high; spikelets very few (1--4), ovate-oblong; bristles plumose below the middle; achene obovate-oblong, bearing a conical tubercle {1/3} its length.--Del.
(_Canby_) to Fla.
[+][+] _Bristles none, or 1--3 and minute; spikelets pale, 1-flowered._
7. R. pallida, M. A. Curtis. Culm (1--2 high) acutely triangular; leaves and spikelets as in the next species, but only a terminal dense cl.u.s.ter, which is less white or turns pale reddish-tawny; achene obovate-lenticular, tipped with a minute depressed and apiculate tubercle; the delicate bristles 4--5 times shorter or obsolete.--Bogs in pine-barrens of N. J. and N. C.
[+][+][+] _Bristles long, denticulate downward, or both ways in n. 11._
[++] _Spikelets white or whitish, becoming tawny with age, perfecting only a single flower; stamens usually 2; bristles 9--12, or even 20._
8. R. alba, Vahl. Culm slender (1--2 high), triangular above; leaves narrowly linear or almost bristle-form; spikelets lanceolate, densely crowded in a head-like terminal corymb and usually one or two lateral ones; achene oblong-obovate with a narrowed base, scarcely longer than the flattened-awl-shaped tubercle, shorter than the bristles.--Bogs, Newf. to Fla., west to N. Ind., Minn., and Oregon. (Eu.)
[++][++] _Spikelets chestnut-colored or darker in_ n. _10 and 11, few--several-flowered; stamens 3; bristles usually 6._
9. R. capillacea, Torr. Culm 6--9' high, slender; _leaves bristle-form; spikelets 3--6 in a terminal cl.u.s.ter_, and commonly 1 or 2 on a remote axillary peduncle, _oblong-lanceolate_ (pale chestnut-color, 3” long); _achene oblong-ovoid_, stipitate, very obscurely wrinkled, about _half the length of the_ (6, rarely 12) _stout bristles_, and twice the length of the lanceolate-beaked tubercle.--Bogs and rocky river-banks, N. Vt.
to Penn., west to western N. Y. and Minn.--Var. LEVISeTA, Hill.
Bristles perfectly smooth. N. W. Ind.
10. R. Knieskernii, Carey. Culm 6--18 high, slender; _leaves narrowly linear_, short; _spikelets numerous, crowded in 4--6 distant cl.u.s.ters, oblong-ovate_ (scarcely 1” long); _achene obovate_, narrowed at base, _equalling the bristles_, twice the length of the triangular flattened tubercle.--Pine-barrens of N. J. (on bog iron ore exclusively) to Va.; rare.
11. R. glomerata, Vahl. Culm 1--3 high; _leaves linear, flat; spikelets numerous in distant cl.u.s.ters or heads_ (often in pairs from the same sheath), _ovoid-oblong_; achene obovate, margined, narrowed at base, as long as the lance-awl-shaped flattened tubercle, which equals the always _downwardly barbed bristles_.--Low grounds, N. Eng. to Fla., west to Mich. and N. Ind.
12. R. cephalantha, Gray. Culm stout (2--3 high); _leaves narrowly linear, flat, keeled; spikelets very numerous, crowded in 2 or 3 or more dense globular_ heads which are distant (and often in pairs), _oblong-lanceolate_, dark brown; achene orbicular-obovate, margined, narrowed at base, about as long as the awl-shaped beak; _bristles_ twice longer, stout, _barbed downward and sometimes also upward_.--Sandy swamps, Long Island to N. J. and Fla.
-- 2. CERATOSCH'NUS. _Spikelets lanceolate, ac.u.minate, in fruit flattish, cymose-panicled, of only one perfect and 1--4 staminate flowers; scales few; bristles rigid, minutely scabrous upward; style simple or barely 2-toothed, filiform and gradually thickened downward, in fruit persistent as an exserted, slender-awl-shaped, upwardly roughened beak, several times longer than the smooth flat obovate achene; coa.r.s.e perennials; spikelets in flower 4”, in fruit including the projecting beak about 1' long._
13. R. corniculata, Gray. (HORNED RUSH.) Culm 3--6 high; leaves about 6” wide; _cymes decompound, diffuse; bristles awl-shaped_, stout, unequal, _shorter than the achene._--Wet places, Penn. to Fla., west to S. Ind. and Mo.
14. R. macrostachya, Torr. (Pl. 4, fig. 1--4.) _Cymes_ decompound, or in the northern form _somewhat simple_ and smaller, and the spikelets usually more cl.u.s.tered; _bristles capillary, twice the length of the achene_.--Borders of ponds, Ma.s.s. to N. J. and Fla.; rare.