572 CYPERACE^. (sedge family.) 



§4. DICLIDIUM. Style 3-cleft; spikelets narrow, terete or nearlji so^feW'- 

 manii-Jiowered, the scales closeli/ appressed and the broad wings oj' the jointed 

 rhachis enclosinrj the triangular acfiene. 



19. C. speciosus, Vahl. Culm stout, mostlij low (5-20' high); rai/s of 

 the simple or compound umbel mostlij all short and croicded ; spikelets 10-20- 

 flowered, yellowish-brown at maturity (3 - 1" loug), the short joints of its axis 

 winged with very broad scaly margins which embrace the ovate triangular 

 achene ; the scales ovate, obtusish, ivibricatelij overlapping. (C. Michauxianus, 

 Gray, Manual; not Schultes.) — Low grounds and sandy banks, N. Eng. to 

 Fla., west to Minn, and Tex. 



20. C. Engelmanili, Steud. Resembles n. 19; but the spikelets more 

 slender and terete, somewhat remotely 5-\o-Jlowered, the zigzag joints of the 

 axis slender and narrowly winged, and the oblong or oval broadly scarious scales 

 proportionally shorter, so as to expose a part of the axis of each joint, the succes- 

 sive scales not reaching the base of the one above on the same side ; achene oblong- 

 linear, very small. — Low grounds, Mass. to Wise, and southward. 



§5. MARISCUS. Spikelets \ -A-Jiowered, subterete, usually in dense heads ; 

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

 the fall of the rest of the spikelet ; joints of the rhachis ivinged, enclosing the 

 triangular achene. Perennial. 



* Spikelets slender and acuminate, more or less refracted in usually close urn- 



belled spikes. — Connecting with § 4. 



21. C. Lancastriensis, Porter. Culm (1-2° high) triangular; leaves 

 rather broadly linear; umbel of 6-9 mostly elongated rays; spikelets very nu- 

 merous in short-oblong close heads, soon reflexed, of 3-6 narrow scales, the 

 upper and lower empty, twice the length of the linear-oblong achene, which 

 is nearly V long. — Rich soil, Peun. and N. J. to Ala. 



22. C. retrofraetUS, Torr. Culm and leaves usually minutely downy 

 and rough on the obtusish angles (1-3° high) ; umbel many -rayed; spikelets 

 slender-awl-shaped, very numerous in obovate or oblong heads terminating the 

 elongated rays, soon strongly reflexed, 1 - 2-Jiowered in the middle (3 - 5" long) ; 

 scales usually 4 or 5, the two lowest ovate and empty, the fertile lanceolate 

 and pointed, the uppermost involute-awl-shaped; achene linear, 1 1" long. — 

 Sandy fields, N. J. to Fla. and Tex. 



23. C. refractus, Engelm. Culm 1-2° high ; rays usually more or less 

 elongated ; spikelets very slender, in rather loose heads, divaricate or more or 

 less reflexed, 2-4-flowered; achene linear, 1:^" long. — N. J. to K C and Mo. 



* * Spikelets very short, blunt, in densely compacted globose or cylindrical heads 



24. C. OVUlaris, Torr. Culm sharply triangular (6' -2° high); umbel 

 1 - 6-rayed ; spikelets (.50 - 100) in a globular head, S-fowered, oblong, blunt (1^- 

 2" long) ; scales ovate, obtuse, a little longer than the ovate-oblong achene. — 

 Sandy dry soil, southern N. Y. to Fla., west to 111., Ark., and Tex. — Var. 

 ROBUSTUS, Boeckl., is a form with large heads (4-8" long), the spikelets 3- 

 4-flowered. (C. Wolfii, Wood.) — IW. to Ark., and southward. 



25. C. Torr^yi, Britton. Like the last, but the heads cylindrical or oh- 

 long, spikelets usually 2-Jiowered, and achene linear-oblong. — L. Island to Fla.. 

 west to Tex. 



