9 S. maritinius L. Sea Bullrush. Culm acutely 3-angled, leafy, 2 - 3f high; lvs. broad-linear, rough-edged, cariuate, taller than the stem; spikes conglomerate, 6 - 10, nearly an inch long, corymbous; invol. of about 3 very long leaves; glumes ovate, 3-cleft, the middle segment subulate and reflexed; style 3-cleft; bristles 3 - 4, much shorter than the broad-obovate, lenticular, dark brown, polished achenium. - Salt marshes, N. Eng. to Flor. Aug.
10 S. fiuviatilis Gray. Culm triangular-winged, leafy, stout, 3 or 4f high; lvs. broadly linear, very long; invol. lvs. 5 to 7, far exceeding the umbel; umbel somewhat compound, spikes separate or conglomerate, large (9 to 12" long), fulvous; glumes 3-cleft, bristles 6, whitish, longer than the sharply 3-angled, oblong, black achenium, which is tipped with a whitish beak. - Borders of lakes and rivers, W. N. Y. and W. States. Jl., Aug. (S. maritimus, ,3. fluv. Torr.)
11 S. atrovirens Muhl. Culm obtusely triangular, leafy, 2f high; cyme compound, proliferous; in vol. of 3 leaf-like bracts longer than the cyme; spikes ovate, acute, crowded, 10 to 20 in a globous head; hds. numerous, 4" diam., dark olive green; glumes ovate, mucronate; bristles 4, straight, hispid downward, as long as the smooth, white achenium. - Common in meadows, Mid. and W. States. Jn., Jl. Very different from S. sylvaticus L. of Europe.
12 S. polyphyllus Vahl. Culm obtusely triangular, leafy, 2 - 3f high; cyme decompound, its principal branches about 5, unequal, with truncate sheaths at base; spikelets clustered in heads of 3 - 6; glumes obtuse, reddish-brown; ach. smooth, yellowish-white, twice shorter than the 4 or 5 smooth tomuous bristles. - Much resembles the last species. Margins of waters, N. Eng., I11. and S. States. (S. brunneus Muhl)
13. S. divaricatus Ell. Culm obtusely triangular, very leafy, 3 to 4f high; lvs. flat, broadly linear or lance-linear, 3 to 6" wide, shorter than the culm; umbel loose, large, decompound, rays filiform, divaricate, recurved; spikes all separate, pendulous, oblong-ovoid, 2 to 3" long, rust colored, pendulous; glumes many, acute; bristles tertuous, rather longer than the achenium which is tawny, elliptic-3-angled, acute at each end. - Wet barrens, S. Car. to La (Hale).
14 S. Eriophoram Mx. Culm obtusely triangular, leafy, 3 to 5f high, lvs. 2f long, rough-edged; invol. 4 cr 5-leaved, longer than the umbel; umbel terminal, decompound, large and loose; spikes mostly pedicillate, 2 to 3" long, ovoid, in smaller clusters; bristles 6, capillary, curled, very conspicuous, being 5 or 6 times as long as the white achenium. - A commen, stiff, rank, meadow sedge, which cattle do not cat, U. S. and Can. Aug. (Tricophorum cyperinum Pers.) Variable. 15 S. lineatus Mx. Culm triangular, very leafy, 2 to 3f high; umbels terminal and axillary, decompound, at length nodding; invol. 1 or 2 bracts, shorter than the umbels; spikes ovoid, pedunculate, solitary; glumes lanceolate, ferruginous; bristles 6, as long as the glumes, hardly exserted. - Swamps in most of the States. Aug. (Tricophorum, Pers.)
7. ERIOPH'ORUM, L. Cotton Grass. (Gr. wool, to bear; alluding to the copious bristles of the perigynium.) Glumes imbricated all around into a spike; achenium invested with many, rarely only 6, very long, dense, woolly or cottony hairs. - Stem generally leafy. Spikelets mostly in umbels, finally clothed with the long, silk hairs.
§ Bristles of the perigynium 6. Spike single..................................................
§ Bristles of the perigynium numberous. - Spike single...................................
- Spikes several. (*)
* Spikes collected into a subsessile, capitate cluster................................
* Spikes separate, pedunculate, in umbellate clusters..............................
Nos. 4, 5
1 E. alpinum L. Culm very slender, acutely 3-angled, naked, somewhat scabrous, 8 - 16' high, with 3 - 4 radical sheaths; radical lvs. very short, subulate; spike oblong, terminal, about 2" in length; hairs 6 to each flower, woolly, white, crisped, 4 times as long as the spike. - Bog meadows, often alpine, N. H. to N. Y. and Penn. Jl.
2 E. vaginatum L. Sheathed Cotton Grass. Sts. densely csespitous, obtusely triangular, slender, smooth and rigid, 1 - 2f high; uppermost sheaths inflated; spikelet ovate, oblong, 6 - 8" long, of a blackish color, with scarious glumes; hairs 30 - 40 to each flower, straight, white and glossy, twice as long as the spikelet, conspicuous, as well as in other species, even at a distance among the meadow grass. - N. Eng. to Mich., N. to Arc. Am. Jn., Jl.
3 E. Virginicum L. Culm strict, firm, slender, tereteish, 2 to 3f high; lvs. smooth, narrowly linear, shorter; invol. 2 to 4-leaved, longer than the inflorescence; spikes many, ovoid, acute, 3" long, glomerate, with very short peduncles, forming a capitate cluster; stam. 1, tawny, exserted with 3 tawny styles; achenium flattened, obovate, keeled on the back, pointed, invested with 70 to 200 pale cinnamon colored setae which arc 4 to 7" long. - Bogs, Can. and U. S. Jl, Aug. In flower the heads are tawny red.
β. confertissimum. Heads very largo (20" diam.) and dense with white seta;. - In Northern N. H. (E. confertissimum Ed. 2d.)
4 E. polystachyon L. Culm somewhat triangular, smooth, 1 - 2f high; cauline lvs. 2 - 3, broad-linear, flattened below, triquetrous at the end; invol. 2-leaved; spikes about 10, on rough peduncles which are long and drooping and sometimes branched; setae 30 - 40 to each flower, white, 6 - 8" long, ach. obovate, obtuse. - Very conspicuous in meadows and swamps, U. S. and Brit. Am.
5 E. gracile Koch. Culm obtusely 3-angled, 18' to 2f high, roughish above; lvs. triquetrous, channeled on the upper side, scarce 1' wide; invol. one-leaved, very short; ped. roughish or subpubescent, nodding; spikes 3 to 8, ovoid, some sub-sessile, others on peduncles 1 to 4" long; glumes striate, brownish; bristles 50 or more in each flower, 8 to 10" long, white; ach. lance-obovate, obtuse. - Bogs, N. States and Can. Common in N. J. (Jackson) (E. angustifolium Torr.).
8. HEMICAR'PHA, Nees. (Gr. half,