CYPERACEiE. (SEDGE FAMILY.) 585 



chestnut-color); achene obovate, half the length nf the bristles, equalling the tri- 

 angular-sword-shapeil acute tubercle, whicli is rough scrruhite on the niargnis. 

 — Low gr.»uii(ls, N. Hrunswick to N. J., west to L. Superior. (Ku.) 



5. R. gracilenta, Ciray. Culms very slender, 1-2° high; leaves nar- 

 rowli/ linear ; spikelets ovoid, in 2 - 4 small clusters, the lateral long-peduncled ; 

 achene ovuid, rather shorter than the bristles, about the length of the Hat awl- 

 shaped tubercle. — Low grounds, southern N. Y. and N. J. to Fla. 



6. R. olig^nthaf Gray. Culm and leaves filiform, 6-12' high; spike- 

 lets very few (1-4), ovate-oblong ; bristles plumose below the middle ; achene; 

 \)bovate-oblong, bearing a conical tubercle ^ its length. — Del. {Canbj) to Fla. 



-t- •»- Bristles none, or \ -3 and minute ; spikelets pale, \-Jiowered. 



7. R. pallida, M.A.Curtis. Culm (1-2*^ liigli) acutely triangular; 

 leaves and sj)ikelets as in the next species, but only a terminal dense cluster, 

 which is less white or turns pale reddish-tawny; achene obovate-lenticular, 

 tipped witli 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. 



H- -t- t- Bristles long, denticulate dowmcard, or both ways in n. 11. 



■^ Spikelets white or whitish, becomin;/ tawny with afje, perfecting only a single 



flower ; stamens usually 2; bristles 9-12, or even 20. 



8. R. ^Iba, 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. \Q and W , few - several flowered ; 

 sta}}iens 3; bristles usually 6. 



9. R. capili^cea, Torr. Culm 6-9' high, slender; leaves bristle form ; 

 spikelets 3-6 in a terminal cluster, 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 //a//' ///e length of the (6, rarely 12) stout 

 bristles, and twice the length of the lanceolate-beaked tubercle. — Boga and 

 rocky river-banks, N. Vt. to I'enn., west to western N. Y. and Minn. — Var. 

 LEVistxA, Hill. Bristles perfectly smooth. N. W. Ind. 



10. R. Kniesk6rnii, Carey. Culm 6-18' high, slender; leaves nar- 

 rowly linear, sliort ; spikelets numerous, crowded in 4-6 distant clusters, 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. 



H. P. glomer^ta, Vahl. Culm 1-3° high; leaves linear, fat; spike- 

 lets numerous in distant clusters 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. cephal^ntha, Gray. Culm stout (2-3° high); /carts narrojr/y 

 linear, fat, keeled ; spikelets very numerous, crowded in 2 or 3 or more dense 

 globular heads which are distant (and often in pairs), obhng-lanceolate, dark 



