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THE NORTH AMERICAN SPECIES OE FUIRENA. 



89 



ANALYSIS OF THE SPECIES OF FUIRENA. 



Leaves, at least the lower ones, reduced to bladeless sheaths. 



Sheaths all bladeless. 1. F. bcirpoidea. 



Upper sheaths with short leaf-blades. 2. F. longa. 



Leaves with well-developed blades. 



Awn, when present, borne on the apex of the sepal, which tapers 



into it. 

 Bristles longer than the perianth-scales and achene. 



Spikelets large, 12 to 20 mm. long. 

 Spikelets small, 5 to 12 mm. long. 



3. F. CYLINDRICA. 

 4. F. SQUAKROSA. 



Bristles reaching ftie middle of the achene, or shorter. 

 Bristles smooth, not exceeding the stipe of the achene. 



5. F. BRKVISETA. 



Bristles smooth, or downwardly barbed, reaching the 



middle of the achene. 



Smooth; stems, leaves and sheaths densely white- 



villous; leaves strongly ciliate. 6. F. ciliata. 



Barbed ; stems, leaves and sheaths somewhat hispid ; 



leaves but little ciliate. 



7. F. IIISPIDA. 



Awn arising from the back of the sepal, just below its apex. 



8. F. SIMPLEX, 



1. FUIRENA SCIRPOIDEA MicllX. 



Fuirena scirpoidea Michx. Fl. Bor. Am. 1 : 38. (1803). 



Eootstocks slender, elongated; stems 2 to 6 dm. tall, 

 widely tufted, very slender, resembling an Eleocharis in 

 appearance ; leaves all reduced to bladeless sheaths ; bracts 

 of the involucre 2 to 6 mm. long,appressed to the spikelets, 

 acute or cuspidate; spikelets sessile, solitary, or 2 to 3 

 together in the clusters, oblong-ovate, 6 to 12 mm. long, 

 dark brown at maturity; scales oblong or obovate, finely 

 pubescent, mucronate or aristate, the points appressed; 

 sepals 3 ; blades obovate-orbicular, obtuse or apiculate at 

 the apices, with a long tapering base about as long as the 

 stalks, scabrous on the upper part of the margins; peri- 

 anth-bristles retrorsely hispid, as long as the stalks of the 

 sepals; achenes triquetrous, constricted at each end, with 

 concave sides, black at maturity, fully 1 mm. long, tipped 

 by the antrorsely hispid style which is one-half as long as 



