O i PE RACEME. 393 



Marshes and swamps. N. Y. and Mass, lo Geor. July. 1. Culms very 

 numerous, slender, diffuse or recurved, prostrate. Scales membranaceous, red- 

 dish-brown on the sides. Achenium light brown. Intermediate Spike Rush. 



7. E. obtusa Schultes : culm terete or slightly compressed, spongy ; spike 

 globose-ovoid, many-flowered ; scales very obtuse ; bristles 6, longer than 

 the obovate lenticular achenium ; tubercle dilated at base. Scirpus capitatus 

 Linn. 



Bogs and low meadows. Can. to Flor. W. to Ohio. June, July. 1\.. 

 Culms 8 15 inches high, cespitose, erect. Spike thick and obtuse, 5080- 

 flowered. Scales with a green midrib. Obtuse Spike Rush. 



*** Spike ovoid. Scales coriaceous. Bristles 6, rigid. Style 3-cleft. 

 Tubercle nearly as large as the achenium. 



8. E. tuberculosa Brown : culm terete, filiform, striate ; spike globose- 

 ovoid, somewhat acute ; scales broad-ovate, very obtuse, loosely appressed ; 

 bristles 6, longer than the oblong and striate achenium ; tubercle large, 

 ovoid, obtuse. Scirpus tuberculosus Mich. 



Sandy swamps. N. Y. and Mass, to Flor. and Louis. Aug. 1\.. Culm 8 12 

 inches high, clothed at base with 1 or 2 sheaths. Spike 12 16-flowered. Scales 

 pale green, or whitish mixed with brown. Large-tubercled Spike Rush. 



**** Spike ovoid or elongated. Scales membranaceous. Bristles 1 4, 

 slender, rarely none. Achenium roundish or triangular. 



9. E. acicularis Drown: culm setaceous, angular; spike ovoid, acute, 

 few-flowered ; scales oblong, rather obtuse ; bristles 4, slender, shorter than 

 the obovate achenium ; tubercle minute. Scirpus acicularis Linn. S. cap- 

 illaceus Mich. 



Margins of ponds. Hudson's Bay to Flor. June, July. QJ.? Culm 2 8 

 inches long, cespitose, slender. Spike 3 8-flowered. Scales greenish with a 

 purple stripe. Capillary Spike Rush. 



10. E. tenuis Schulies : culm filiform, angular, the sides concave ; spike 

 elliptic, acute at each end ; scales ovate, obtuse ; bristles 2, 3, or none ; 

 achenium obovoid-triangular, rugose ; tubercle minute, triangular. Scirpus 

 tenuis Willd. 



Swamps and wet meadows. Can. to Car. W. to Ark. July. 7J.. Culm 

 8 12 inches long, very slender, w'ith one or two purple sheaths at base. Spike 

 when young somewhat obtuse. Scales dark chestnut color, with the margins 

 white. Slender Spike Rush. 



11. E. melanocarpa Torr. : culm compressed, sulcate; spike oblong or 

 cylindric-oblong ; scales ovate, obtuse, membranaceous ; bristles 3 4, 

 slender, mostly as long as the somewhat turbinate and obtusely triangular 

 achenium ; tubercle broad, triangular, short-acuminate. 



Borders of swamps. N. Y. to Geor. May, June. 7|.. Culm 12 18 inches 

 high, tough, sulcate. Spikes 4 6-lines long, thick, many-flowered. Bristles 

 sometimes very short. Black-fruited Spike Rush. 



***** Spike compressed, often somewhat distichous. Scales membranaceous. 

 Bristles slender. Style 3-cleft. Achenium triangular. 



12. E. pigmcea Torr. : culm setaceous or acicular, much compressed and 

 sulcate ; spike ovate-compressed, few-flowered ; scales ovate ; bristles 6 



17* 



