46 CYPEBACEAE. 



7. Cyperus rotundus L. Sp. PI. 45. 1753. 



Perennial by scaly tuber-bearing rootstocks; culm rather stout, 0.1-0.5 m. 

 high, usually longer than the leaves. Leaves 3-6 mm. wide, those of the in- 

 volucre 3-5; umbel 3-8-rayed, the longer rays 5-11 cm. long; spikelets linear, 

 clustered, few in each cluster, acute, 8-20 mm. long, 2-3 mm. wide ; scales dark 

 purple-brown or with green margins and centre, ovate, acute, appressed when 

 mature, about 3-nerved on the keel; stamens 3; style 3-cleft, its branches ex- 

 serted; achene 3-angled, about one-half as long as the scale. 



Waste and cultivated grounds, New Providence : United States ; Bermuda ; 

 West Indies : tropical continental America ; warm-temperate and tropical parts of 

 the Old World. NUT-GRASS. 



8. Cyperus floridanus Britton; Small, Fl. S. E. U. S. 170. 1903. 



Perennial by tuber-like bases of the culms. 'Culms filiform, wiry, densely 

 clustered, erect or reclining, 0.5-2.5 dm. long; leaves filiform, or the lowest 

 reduced to scales, some of them usually as long as the culm or longer, about 

 0.5 mm. wide, those of the involucre 2 or 3, similar to the lower ones, the 

 longer much exceeding the head of spikelets, sometimes 10 cm. long; head 

 composed of few to several spikelets; spikelets digitate, flattened, linear- 

 subulate, 6-15 mm. long, 1 mm. wide, several-flowered, acuminate; scales 

 oblong, 2 mm. long, chestnut-brown, blunt, strongly several-nerved, firm in 

 texture; stamens 3; achene linear-oblong, about 1.5 mm. long and 0.5 mm. 

 thick, dull, dark brown. Plant with the habit of C. filiformis. 



Moist sandy soil, Abaco, Berry Islands, Andros, New Providence : Florida ; 

 Cuba ; Santo Domingo. FLORIDA CYPERUS. 



9. Cyperus fuligineus Chapm. Fl. S. States 511. 1860. 



Mariscus fuligineus Clarke, Kew Bull. Add. Ser. 8 : 16. 1908. 



Perennial; culms very slender, smooth, tufted, 1-4 dm. high, rather rigid. 

 Leaves revolute-margined, shorter than the culm, those of the involucre usually 

 2, unequal; spikelets linear, 6-10 mm. long, 1-1.5 mm. wide, densely crowded 

 in a single terminal head; scales ovate to oval, about 2 mm. long, dark brown, 

 striate, mucronulate; style 3-cleft; achenes oblong-obovoid, trigonous, about 

 1.5 mm. long, dull, brown. 



Sandy and rocky soil, Berry Islands, New Providence and Eleuthera to Am- 

 bergris Cay, Grand Turk, Inagua and the Anguilla Isles : Florida ; Cuban Cays ; 

 Anegada ; Bonaire ; Curagao. Recorded by Coker and presumably by Dolley as O. 

 Vahlii Steud. ; by Hitchcock as C. brunneus Sw. 



10. Cyperus ligularis L. Amoen. Acad. 5: 391. 1759. 



Perennial; roots fibrous, thick; rootstock short or none; culms stout, 1.2 

 m. high or less. Leaves 8-20 mm. wide, pale green, rough-margined, the 

 basal ones often overtopping the culm, those of the involucre sometimes 7 dm. 

 long; umbel 4-12-rayed, large, compound; spikes oblong or subglobose, 8-10 

 mm. thick, very dense; spikelets gray to brown, 4-6 mm. long, about 1.5 mm. 

 wide, bearing 2-4 achenes; fruiting scales oval or ovate, striate, blunt, 2.5-3 

 mm. long; achene narrowly obovoid to ellipsoid, dark brown, dull, 3-angled, 

 about 1.5 mm. long, half as long as the scale. 



Swamps, Great Bahama to Andros, New Providence. Fortune Island, North 

 Caicos and Inagua : southern United States : West Indies and tropical continental 

 America ; tropical Africa. LARGE CYPERUS. SAW-GRASS. 



11. Cyperus brunneus Sw. Fl. Ind. Occ. 1: 116. 1797. 

 Mariscus 'brizaeus Clarke in Urban, Symb. Ant. 2: 52. 1900. 



Perennial by stout rootstocks; culms stout, 7 dm. high or less. Leaves 

 4-10 mm. wide, pale green, the basal often overtopping the culm, those of the 

 involucre 3-5, the longer much surpassing the inflorescence; umbel few-rayed, 



