20 C. Grayii Torr. Culm 8 - 12' high, filiform, obtusely triangular, erect, tuberous at base; lvs. radical, channeled, about 1/2" wide; umbel 4 - 6-rayed capillary, erect, spreading; sheaths truncate; hds, loose, of 6 - 8 spikelets; spikelets linear, compressed, 8 - 7-flowered; scales ovate, veined, obtuse, imbricated, interior ones lanceolate; sta. 3; sty. 3-cleft; ach. obovate-triquetrous, 2/3 the length of the scale, gray, dotted. - Sandy fields, Mass. to N. J. Sept.
21 C. filiculmis Vahl. Culm slender, almost filiform, tuberous at base, 8 - 12' long, leafy only at base; lvs. mostly radical, carinate; umbel simple and sessile, or with 1 or 2 rays; spikes linear-lanceolate, 3 - 8-flowered, flattened when old, collected into globous heads; glumes remote, loose, ovate, yellowish. - Dry, rocky hills, ft. Eng. to Fla., W. to III. Aug. (C. mariscoides Ell.)
22 C. compressus L. Culm naked, 3-angled, 3 to 8' high, tumid at base; umbel sessile or simple and few-rayed, rays spreading; spikes lanceolate, 2-edged,
12 to 40-flowered, loosely aggregated in heads; rachis winged; glumes ovate, slightly veined, acuminate, yellowish, very acutely keeled; stam. 3; ach. obovate, 3-angled, shining. - Dry fields, S, States. Spikes 6 to 12" long, sharply serrated by the projecting points of the glumes. Root fibrous.
23 C. dentatus Torr. Culm about If high, leafy at base, triquetrous; lvs. a little shorter than the stem, strongly keeled; umbel compound, 6 - 10-rayed; invol. of 3 unequal leaves, one of them longer than the umbel; spikes 3 on each peduncle, 3 - 7", lance-ovate, flat, 8 (rarely 5 to 30) flowered; glumes acute, spreading at the points, giving the spikes a serrated appearance; sty. 3-eleft; ach. triangular. - Swamps, Mass., to N. Y. and Fla. Rhizome creeping, bearing tubers. Spikes often morbidly enlarged.
24 C. Lecontii Torr. Culm 3-angled 1 to 2f high, leafy at base; lvs. linear, about the same height; invol 3 to 6-lvd., longer than the umbel; umbel compound, many-rayed; spikes oblong, obtuse, flat, in small digitate clusters, 20 to 40-flowered; glumes closely imbricated, acute, yellowish, the points obtusish, callous, scarcely separated; stam. 3. - Fla.! to La. An elegant species. Spikes 4 to 7" by 2". Rhizome creeping.
25. C. leptos Schultes. Culm weak, 1 to 2f high, 3-angled; lvs. radical, shorter; umbel compound or decompound, of numerous (12 to 15) filiform rays, with ashort, 2-leaved involucre; spikes 3 to 5 in each loose head, lance-linear, 12 to 20-flow-cred; glumes ovate-lanceolate, acute, keeled, the keel green, sides yellow with 2 rod lines. - Damp soils, N. Car. to Fla. and La. Spikes 3 to 4" long. Sept., Oct. (C. gracilis Muhl.)
26 C. ovularis Vahl. Culm acutely 3-angled, nearly naked, 6 to 16' high; lvs. shorter, nearly smooth; umbel simple; rays 3" to 2' long; hds. 1 to 5, globular, one sessile, the rest on the spreading rays; spikes linear-subulate, 3" long, 50 to 100 in each head; fls. 2 to 4, 1 or 2 fertile; invol 3 or 4-leaved, outer lvs. very long; glumes ovate, obtuse, greenish, the two lowest empty. - Bogs and low grounds, M, W. and S. States, common. Aug., Sept. (Maxiscus Vahl. Kyl-lingia Mx.)
27 C. retrofractus Vahl. Culm obtusely triangular, nearly leafless, pubescent, 2 to 3f high; lvs. pubescent, 3 to 4" wide, about half as long as the stem; umbels simple; rays unequal, long, 6 to 8; invol. 3 to 5-leaved; bracts unequal, not longer than the rays; spikes 70 to 100, subulata, 1-flowered, finally retrorsely imbricate into obovate heads; 2 lower glume3 empty. - Mid., W. and S. States, rare northward. Aug., Sept.
3. KYLLIN'GIA, L. (In honor of Peter Kylling, a Danish botanist.) Spikes compressed; scales about 4, the 2 lowest short and empty, the third only usually with a fertile flower; stamens 1 to 3; style long, 2-cleft; achenia lenticular. - Sts. triangular. Hds. sessile, solitary or aggregated, involucrate.
1 K. pumila Mx. Caespitous; culm 2 to 12' high, slendsr; lvs. mostly radical, shorter than the stem, smooth; hds. generally solitary, sometimes triple, closely sessile, oval or oblong; invol 3-leaved, 1 to 2' long; spikes 1-flowered, very numerous, about 2" long; the lowest glume or glumes very small; sta. always 2; ach. lens-shaped, fulvous. - Wet banks, Columbus, Ohio (Sullivant) to I11. (Lap-ham) and S. States. Variable. Aug. K. sesquiflora Torr. is a taller form, with triple heads. (Florida, Chapman.)
4. FUIRE'NA, Rotboll. Clot-grass. (In honor of George Fuiren, a Dutch botanist.) Glumes imbricated on all sides into a spike, awned below the apex; petaloid scales 3, cordate, awned, nnguiculate, investing the achenium, which is abruptly contracted to a stipe at base. - St. angular, leafy. Spikes umbeled or capitate, axillary and terminal.
1 P. squarrosa Mx. Culm 1 to 2f high, obtusely triangular, sulcate; lvs. flat, ciiiate, shorter than the stem; sheaths hispid-pilous; spikes clustered, ovoid, mostly terminal, 7 to 12; awns nearly as long as the glumes; petals ovate, cusp:date with a short bristle; ach. twice the length of the stipe. - Bogs and swamps, Mass. to Mich., S. to Fla. and La. β. pumila. Culm a few (3 to 6) inches high , spikes 1, 2 or 3; glumes ovate-lanceolate, with short awns; petaloid scales ovate-lanceolate.
2 F. hispida Ell. Culm triangular, sulcate, hispid above, 2 to 3f high; lvs. linear, 5 to 8' long, flat, hispid-pubescent, with very hispid sheaths; spikes 3 to 12, in clusters of 3 to 6, ovoid-oblong, mostly terminal; awns longer than the glumes, spread-iug-recurved; petals ovate, mucronate; stam. 3, scarcely longer than the corolla; sty. twice as long as the stamens. - Car. to Fla. and La. Differs from No. 1 chiefly in its hairiness.
3 F. scirpoidea Mx. Culm slender, 1 to 2f high, 3-angled, striate, leafless, but with several sheaths; spikes 1 to 6, ovoid, terminal, dingy brown, not squarrous; glumes short atoned or cuspidate; petals ovate, shorter than the claws; stam. 3; ach. triangular, pointed at both ends. - S. Ga. and Fla. Rhizome creeping. Heads as large as the white bean.