TRIANDRIA MONOGYNIA. 301 



19. SCIRPUS. Club-rush. 



* Seed surrounded with bristles at the base. 



t Style articulated to the seed ; base dilated and persistent. Seed often 



lenticular. Spike solitary. 



S. tennis : culm very slender, quadrangular ; spike elliptical, acute at 

 each end ; glumes ovate, obtuse ; stamens 3 ; style 3-cleft ; seed 

 rugose 

 HAB. Wet places. July Aug. %.. Culm naked, 8 12 in. high ; 



head brown ; bristles 2 3, sometimes wanting. 



S. palustris : culm terete, inflated ; spike oblong-lanceolate ; glumes 

 somewhat obtuse ; seed roundish, punctate and rugose ; bristles 

 scabrous. 

 HAB. Wet places. June 7J.. Cespitose ; culm I 2ft. high, sheathed 



at the base, leafless ^ seed crowned with a conical tubercle. 

 S. capitalus : stem terete, or somewhat compressed ; spike ovate, obtuse ; 



seed oval, compressed, smooth. 

 HAB. Wet places. July Aug. 7|.. Cespitose ; culm attenuated 



below the spike ; spike often globose ; bristles 6. 



S. acicularis : culm setaceous, quadrangular ; spike ovate, acute, 3 6- 

 flowered ; glumes somewhat obtuse ; stamens 3 ; style bifid ; seed 

 obovate. 

 HAB. Border of ponds. June July. 1|.. Culm almost hair-like ; 



inf. glume empty, large ; seed striate ; bristles 4. 



S. intermedius : culms cespitose, quadrangular, sulcate; spike ovate- 

 oblong, acute ; glumes rather acute ; stamens 3 ; style 2-cleft ; seed 

 broad obovate, compressed ; tubercle distinct. 

 HAB. Muddy banks of rivers. Sept. 7J.. Ascending 34 in. high ; 



bristles 6 ; tubercle very minute. 



S. planifolius : culm triquetrous ; radical leaves flat ; nearly equalling 

 the culm ; spike terminal, oblong, compressed, shorter than the cus- 

 pidate bracts at the base. 



HAB. Bogs and wet woods. May June. 7].. Cespitose ; leaves 

 carinate ; spike 6-fl. yellowish ; inf. glumes very large, bracteiform. 



t t Style filiform, not bearded, deciduous. 



S. americanus : culm nearly naked, triquetrous ; sides concave ; spikes 

 lateral, (1 5,) ovate, conglomerate, sessile; glumes round-ovate, 

 mucronate ; seed triquetrous, acuminate. 

 HAB. In salt marshes, and on the banks of rivers. July Aug. 1L. 



Culm 3 &ft. high, sometimes leafy at base. 

 S. debilis : culms cespitose, deeply striate ; spikes about 3, lateral, 



ovate, sessile ; glumes, ovate, obtuse, mucronate. 

 HAB. Borders of ponds. Aug. Sept. Tj.. A foot high ; leaves few, 



subulate ; spikes turgid ; seed obovate ; bristles 4 5. 

 S. lacustris : culm terete, attenuated above, naked ; panicle subtermi- 



nal ; spikes peduncled, ovate. 



HAB. Ponds and river marshes. June. r l\.. Culm 4 8ft. high, 

 sheathed at the base ; spike subpaniclcd ; glum, ovate, subpubescent ; 

 seed obovate. 

 S. acutus : culm terete, (not attenuated,) spotted ; peduncles numerous ; 



sublateral ; spikes oblong ; glumes pubescent, mucronate. 

 HAB. Ponds and wet swamps. June July. TJ.. Culm 4ft. high t 

 with oblong brown spots ; panicle proliferous ; glum, dilated) cari~ 

 note. 



