244 



CYPERACEAE. 

 Cyperus refractus Engelm. Reflexed Cyperus. (Fig. 566.) 



Cy perus refractus Engelm. ; Boeckl. Linnaea, 36: 369. 

 1869-70. 



Perennial by tuber-like conns, culm stout, 

 smooth, i-3 tall. Leaves 2^ // -4 // wide, rough- 

 margined, elongated; umbel 6-i3-rayed, usually 

 compound, the longer rays sometimes 8' long, 

 their sheaths terminating in i or 2 short teeth; in- 

 volucels setaceous; raylets filiform; spikelets very 

 narrowly linear, loosely spicate, acute, flattish, 

 5 // -i2 // long, y 2 ff thick, 3-6-flowered, the upper 

 spreading, the lower reflexed; scales yellowish- 

 green, oblong-lanceolate, obtuse, closely appressed, 

 9-n-nerved, thin; stamens 3; style 3-cleft, its 

 branches much exserted; achene narrowly linear, 

 obtuse, apiculate, about 5 times as long as thick, 

 and one-half as long as the scale. 



In dry fields, New Jersey to North Carolina and 

 Missouri. July-Sept. 



25. Cyperus retrofractus (I,.) Torr. Rough Cyperus. (Fig. 567.) 



Scirpus retrofractus L. Sp. PI. 50. 1753. 



Cyperus retrofractus Torr. ; A. Gray, Man. 519. 1848. 



Perennial by tuber-like corms, culm slender, 

 rough-puberulent, at least above, mostly longer than 

 the puberulent leaves, i-3 tall. Leaves \W~zW 

 wide, those of the involucre 4-7, the longer not 

 greatly exceeding the umbel, sometimes shorter; um- 

 bel simple; rays very slender, nearly erect, or spread- 

 ing, 2 / -6 / long, their sheaths 2-toothed; heads ob- 

 long or obovoid; spikelets linear- subulate, ^ // -6 // 

 long, about y 2 " thick, i-2-flowered, all soon strongly 

 reflexed, separating from the axis at maturity; flow- 

 ering scales lanceolate, acute, the upper one subu- 

 late, all strongly several-nerved; stamens 3; style 

 3-cleft; achene linear, 3-angled, obtuse, apiculate, 

 two-thirds as long as the scale. 



In dry, sandy soil, southern New Jersey to Florida, 

 west to Kentucky, Arkansas and Texas. July-Sept. 



26. Cyperus Lancastriensis Porter. Lancaster Cyperus. (Fig. 568.) 



Cyperus Lancastriensis Porter; A. Gray, Man. Ed. 5, 

 555- 1867. 



Perennial by ovoid or oblong corms, culm slender, 

 smooth, mostly longer than the leaves, i-2 l / 2 tall. 

 Leaves 2 // ~3 // wide, those of the involucre 4-7, the 

 longer much exceeding the inflorescence; umbel 

 simple, s-g-rayed, the longer rays 2 / -4 / long, their 

 sheaths nearly truncate; heads oval, obtuse, %'-i' 

 long; spikelets densely clustered, 4 // ~5 // long, linear, 

 subterete, 2-4-flowered, the lower reflexed, the mid- 

 dle ones spreading, all separating from the axis at 

 maturity; scales green, strongly several-nerved, the 

 flowering ones lanceolate, subacute; stamens 3; 

 style 3-cleft; achene linear, obtuse, apiculate, 2-3 

 times as long as thick, two-thirds as long as the 

 scale. 



In dry fields, New Jersey and Pennsylvania to Vir- 

 ginia and Alabama. July-Sept. 



