CYPERACE.E. (SEDGE FAMILY.) 585 



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

 augular-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 nar- 

 row/// linear ; spikelets ovoid, in 2 - 4 small clusters, 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; spike- 

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

 obovate-oblong, bearing a conical tubercle | its length. Del. (Canby) to Fla. 



-i- -i- Bristles none, or 1-3 and minute; spikelets pale, l-Jiowered. 



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 cluster, 

 which is less white or turns pale reddish-tawny ; acheue 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. 



K H- H- Bristles long, denticulate downward, or both ways in n. 11. 



w- Spikelets white or whitish, becoming tawny with age, perfecting only a single 



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



8. B. 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 flatteued-awl- 

 shaped tubercle, shorter than the bristles. Bogs, Newf. to Fla., west to N. 

 Ind., Minn., and Oregon. (Eu.) 



M- -t-t- Spikelets chestnut-colored or darker in n. 10 and \\, few several-flowered ; 



stamens .3 ; bristles usually 6. 



9. R. capiliaC6a, Torr. Culm 6-9' high, slender ; leaves bristle-form; 

 spikelets 3-6 I'M 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 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 Penu., west to western N". Y. and Minn. Yar. 

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



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

 rowly linear, short; spikelets numerous, crowded in 4-6 distant clusters, obloni/- 

 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. F. glomerata, Vahl. Culm 1-3 high; leaves linear, fiat; 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. 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 



