CYPERACE.E. (SEDGE FAMILY.) 369 



flattened tuberculate base persistent and mostly jointed upon the summit of 

 the turgid-triangular or lenticular akeue. Stems tufted, from matted or 

 creeping rootstocks, terete or angular, the base covered with closely appressed 

 sheaths : lower scale of the spikelet sometimes enlarged and bract-like. 



* Spike small and few -flowered, the scales somewhat distichous or only 3-ranked : 



style 3-cleft and akene triangular. 

 t- Tubercle contracted at its junction with the akene, 



t. E. acicularis, R. Br. Stems with fibrous roots and very slender run- 

 ning rootstocks, usually setaceous, 1 to 8 inches high : spike 3 to 9-flowered : 

 scales acutish, more or less deeply tinged with brown : bristles 3 or 4, often 

 wanting: akene oblong-obovate, obscurely triangular and faintly ribbed on 

 the sides; tubercle broad, short and blunt. On sandy or muddy stream- 

 banks across the continent. 



+- H Tubercle continuous with the akene and not contracted at base. 



2. E. pauciflora, Watson. Stems from slender running rootstocks, 3 to 

 8 inches high, striate: spike ovate-oblong: scales acute, dark brown: bristles 

 3 to 6, usually equalling the akene : akene oblong-obovate, obtusely triangular ; 

 tubercle rather stout, pyramidal, nearly a third as long as the akene. Bot. 

 Calif, ii. 221. Scirpus paucifloms, Lightfoot, Gray's Manual, 560. From 

 Colorado and Wyoming to the N. Atlantic States ; also in California. 



* * Spike terete, man '/-flowered : tubercle somewhat contracted at its junction with 



the akene : st'/le 2-cleft and akene lenticular. 



3. E. palustris, R. Br. Stems usually slender, terete, striate, to 4 feet 

 high : spike oblong-lanceolate to linear, acute, 3 to 12 lines long : scales obtuse or 

 the upper acutish, thin, brown with white margin and greenish keel : bristles 4, 

 about equalling the akene: akene obovate, turgid, smooth ; tubercle broad-deltoid, 

 acutish or acute, rarely acuminate. Throughout the continent, and in most 

 parts of the Old World. 



4. E. olivacea, Torr. Stems very slender and spreading, 1 to 6 inches 

 high : spike ovate or oblong-ovate, 1 to 3 lines long : scales obtuse, rather loosely 

 imbricated, purple with a green midrib : bristles 6 or 8, longer than the akene : 

 akene and tubercle as in the last. Colorado, Montana, and Oregon ; also on 

 the Great Lakes and the Atlantic coast. 



5. E. COmpressa, Sulliv. Stem flat, striate, 1 to 2 feet high : spike ovate- 

 oblong, at length lanceolate, 4 to 7 lines long : scales acute, dark purple with 

 broad white pellucid margins: bristles 1 to 4 (or none), very slender and fragile, 

 shorter than or equalling the akene : akene obovate-pear-shaped, compressed ; tuber- 

 cle small, conical, pointed. Gray's Manual, 558. 



6. FIMBRISTYLIS, Vahl. 



Scales closely imbricated around the rhachis. Styles 2 to 3-cleft, often flat- 

 tened and ciliate, somewhat dilated at base. Akene lenticular or triangular, 

 usually attenuate at base or suustipitate. In ours the style is 2-cleft and the 

 akene lenticular. 



1. F. spadicea, Vahl. Stems 1 to 2 feet high, from a perennial root, 

 rigid, as are the filiform convolute-channelled leaves : spikes ovate-oblong, becom- 



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