CYPERACEAE (SEDGE FAMILY^ 



1< i 



19. C. erythrorhizos Mnhl. Annual ; culm obtusely 

 triangular (1-8 dm. high); umbel many-rayed; invo- 

 lucre 4— 5-leaved, very long ; involucels bristle-form : 

 spikelets very numerous, crowded in oblong or cylindrical 

 nearly sessile beads, spreading horizontally, linear, Jlat- 

 tish (o-lO mm. Jong), blight chestnut-colored; scales 



lanceolate, raucrunulate. (C Halei 

 Britton, in part, not Torr.) — Allu- 

 vial banks, Mass. to Ont., Minn., 

 and southw. Fio. 219. — Dwarf 

 tutted plants are sometimes sepa- 

 rated as Var. pumilus Engelm. 



20. C. ferax Rich. Culm stout, 

 mostly hue (0.3-8 dm. high) ; rays 



<if the simple or compound umbel mostly all short and 

 crowded ; spikelets lO-20-flowered, yellowish-broion or drab 

 at maturity (0.5-1.8 cm. long), the short joints of its axis 

 winged with very broad scaly margins which embrace the 

 ovoid-triangular achene ; the fir ra scales ovate, obtusish, 

 overlapping. (C. speciosus Vahl.) — Low grounds and 

 to Fla., w. to Ont., Minn., and Tex. ; Cal. (Trop. re- 





219. C. erythrorhizos. 



\ 



ferax. 



•J-21. C. Euffelmaniii. 



222. C. strigosus. 



sandy banks, Mass. 



gions.) Fig. 220. 



21. C. Engelmanni Steud. Similar ; but the spikelets more slender and terete, 



somewhat remotely o-lb-flowered, the zigzag- joints of the axis slender and nar- 

 rowly winged, and the oblong or oval broadly scarious 



scales proportionally shorter, so as to expose a part of the 



axis of each joint; achene oblong-linear, very small. — 



Low grounds, Mass. to Wise, 

 and south w. Fig. 221. 



22. C. strig5sus L. Peren- 

 nial, with hard corm-like 

 tubers ; culm 0.1-1 m. high ; 

 leaves flat, soft ; most of the 

 rays of the simple or com- 

 pound umbel elongated, their 

 sheaths 2-bristled ; spikelets 

 several-flowered. 0.7-1.8 cm. 



long, spreading, in loose heads ; scales oblong- 

 lanceolate, appressed, several-nerved, much longer 

 than the linear-oblong achene. — Damp or fertile 

 soil. Me. to Ont., Minn., south w. and westw. Fig. 



222. — Very variable ; dwarf plants with the rays scarcely developed are Var. 



CAPTTATus Boeckl. 



Var. robustior Kunth. Spikelets 2-3 cm. long. — Local, 



Mass. to Fla. and Mo. 



Var. comp6situs Britton. Umbel compound; spikelets O.b- 



1.3 cm. long, in dense cylindric heads. — Local, Mass. to Fla.. 



La., and la. 



23. C. refrdctus Engelm. Culm smooth, 3-9 dm. high : 

 leaves soft and flat, 4-8 mm. broad, slightly scabrous ; ray.^ 

 usually more or less elongated, smooth ; spikelets very slender, 

 acuminate, suhterete, in rather loose heads, divaricate or more 

 or less reflexed, 2-6-floioered, 1-3 cm. long; scales appressed. 

 several-nerved, the lower empty and often persistent after the 

 fall of the rest ; joints of the rhachilla winged, inclosing the 

 linear achene. — Dry woods and banks, N. J. to Ga. and Mo. 

 Fig. 223. 



24. C. lancastriensis Porter. Culm stoutish, triangular, 

 smooth, 3-8 dm. high; leaves rather broad (0.5-1 cm.) ; umbel 

 of 6-9 mostly elongated rays ; spikelets very numerous in 



gray's manual — 12 



223. C. refractus. 



