74'0 ORDER 155. CYPERACE^E. 



cattle do not eat, 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. gpiov, wool, 0t'po>, to 

 bear ; alluding to the copious bristles of the perigynium.) Glumes im- 

 bricated all around into a spike ; acheniuin invested with many, rarely 

 only 6, very long, dense, Avoolly or cottony hairs. Stem generally leafy. 

 Spikelets mostly in umbels, finally clothed with the long, silk hairs. 



Bristles of the perigynium 6. Spike single No. 1 



Bristles of the perigynium numerous. Spike single , No. 2 



Spikes several. (*) 



* Spikes collected into a subsessile, capitate cluster No. 3 



* Spikes separate, pedunculate, in umbellate clusters Nos. 4, 5 



1 B. alpinum L. Culm very slender, acutely 3-angled, naked, somewhat sca- 

 brous, 8 16' high, with 3 4 radical sheaths; radical Ivs. 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, G 8" long, of a blackish color, with scarious glumes ; 

 hairs 30 40 to each flower, straight, white and glossy, twice as long aa the 

 spikelet, conspicuous, as well as in other species, even at a distance ahiong 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 ; Ivs. 

 smooth, narrowly linear, shorter ; invol. 2 to 4-leaved, longer than the inflores- 

 cence ; spikes many, ovoid, acute, 3" long, glomerate, with very short peduncles, 

 forming a capitate cluster ; stam. 1, tawny, exserted with 3 tawny styles ; ache- 

 nium flattened, obovate, keeled on the back, pointed, invested with 70 to 200 

 pale cinnamon colored setse which arc 4 to 7" long. Bogs, Can. and U. S. JL, 

 Aug. In flower the heads are tawny red. 



8. CONFERTISSIMUM. Heads very largo (20" diam.) and dense with white setse. 

 In Northern N. II. (E. confertissimum Ed. 2d.) 



4 E. polystachyon L. Culm somewhat triangular, smooth, 1 2f high ; cauline 

 Ivs. 2 3, broad-linear, flattened below, triquetrous at the end; invol. 1-leaved; 

 spikes about 10, on rough peduncles which are long and drooping and sometimes 

 branched; setse 30 40 to each flower, white, G 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; Ivs. 

 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, Nces. (Gr. fywovf, half, Kdpfa, straw or chaff, 

 there being but one scale to the flower.) Spike many-flowered ; glumes 

 imbricated all around ; interior scale 1, embracing the flower and fruit; 

 bristles ; stamens 1 ; style 2-cleft, not bulbous at base, deciduous ; 

 achenium compressed, oblong, subterete. Z Low, tufted, with seta- 

 ceous culms and leaves. 



H. subsquarrosa Xces. Culm setaceous, compressed, sulcate, recurved, 2 3' 

 high; Ivs. setaceous, shorter than the scape; spikes 2 3, terminal (appa' 

 rently lateral), subsessile, ovoid, nearly 2" long; invol. of 2 bracts, one appear- 



