214 CYPERACE.E. Cyperus. 



§ 1. Sti/h 2-cleft and nutlet lenticular, the edge turned to tlie r/tac/iis: spihelet 

 Jlattened, manj/-f{oivered, the scales folded and sliarplij carlnate : rhachis 

 narroiv, not wimjed. — Pvchkus, Toir. 



1. C. diandrus, Torr. Annual, witli fibrous roots, and very slender triangular 

 clustered stems h to 2 feet high : leaves elongated, very narrow (rarely a line wide) : 

 involucre 2 - 3-leavetl : spikelets in a sessile compound cluster or in loose clusters 

 upon the few sliort raya, linear-oblong, acute, 3 to G lines long : scales pale or brown- 

 ish, thin and usually lax, rather obtuse, 1 to 1;^ lines long, twice longer than tlie 

 light or dark brown oblong-ovate dull nutlet : stamens 2 or 3 : style elongated, often 

 cleft nearly to the base. 



Var. castaneus, Torr. Scales more firm and often brown : styles less elon- 

 gated, cleft to tiie middle. — C. castautus, liigel. C. tenellus, Presl, IJel. Ilajnk. 

 i. 170? C. rivnlaris, Kunth, Euum. ii. G; Loeckeler, Linuica, xxxv. 452. 



The variety only has bi-eii collectetl in Californiii, in swamjis near San Francisco (liafandcr) axn\ 

 in tlie valley of the Sacramento (l'icLcri)i(j), but both forms are common in the Atlantic. States 

 and west to Texas anil New Alexico. Nutlet rather longer and less pointed than in the eastern 

 forms. It is probable that the C. comprcssus, as well as the C. tenellus, of Haenke's collection, 

 reported as found at Monterey, is to be referred to this species. 



§ 2. Style 2-cleft and nutlet pla7iO'Convex, flattened parallel with the rhachis: 

 spikelets flattened but thick, the concave scales scarcely carlnate, and the 

 broad rhachis not ivimjed. — Juncellus, Griseb. 



2. C. laevigatus, Linn. Perennial, Avith slender creeping rhizome : stems 

 numerous, sleniler, 3 to G inches high or more, terete, naked excepting 2 or 3 short 

 brown sheaths at base, of which the upper bears a short erect subtriangular leaf : in- 

 volucre of usually 2 bracts, one erect in continuation of the culm, the other very 

 short or wanting : spikelets 2 or 3 or more, sessile in an apparently lateral cluster, 

 linear-oblong, many-flowered, 2 or 3 lines long, obtuse or acutish, pale green or 

 sometimes lirown : scales broad and concave, obtuse, scarcely nerved, nearly a line 

 long : rhachis deeply pitted transversely : stamens 3 : nutlet broadly obovate, \ line 

 long. — Boeck. 1. c. 48G. C. mucronatus, Ifottb. 



At Los Angeles (Brewer) and at hot springs near San Bernardino, IF. G. ITriifht. A widely 

 distributed species in warm regions, collected in Mexico by llarlweg, and founil in ri-ru, the 

 Sandwich Islands, Australia, India, at the Caiie of (Jood Hope, and in the Mediterranean region. 



§ 3. Style 3-cleft and nutlet triangular : spikelets many floivered, flattened with 

 carinate scales, the rhachis naked or very nearly so. — Eucypkkus. 



* A small annual: spikelets with acuminate scales, in a few dense heads: 



stamen solitary. 



3. C. aristatUS, Pottb. Stems ^ to 6 inches high, about eciualling the flat 

 leaves, with conspicuous involucres : spikelets linear-oblong, 2 to 5 lines long, in a 

 dense compound sessile head or in close clusters upon 2 or 3 usually short rays : 

 scales with .strongly recurved setaceous tips, chestnut brown, about a line long, twice 

 longer than the oblong-obovate obtuse apiculate brownisli nutlet. — C. inflexns, 

 Muhl. C. aureus, Presl, 1. c. 1G8. 



A common species througliout the State, from Lower Onlifornia to Oregon and across the con- 

 tinent ; it is also found in Mexico, Africa and the East Iiulies. 



C. ACUMlNATUs, Torr., is somewhat taller and stouter (3 to 12 inches high), with fewer and 

 broadei' oblong-ovate straw-colored spikelets, and short-acuminate spreailing or very slightly re- 

 curved scales : nutlet oidong-obovate, acutish at each end. A species of the Mississippi \'alley, 

 from Illinois to Texas, which has been found iu Oregon, Hall, Ilorcell. 



* * Tall p)erennial : spjikelets short, with green obtusish spreading scales, in 



dense heads. 



4. C. virens, I^Iichx. Stout, 1 to 4 feet high : leaves and bracts of the involucre 

 very long, broad and strongly keeled : umbel compound, often much reduced and 



