CYPERACE^ 13 



bearing long, often twisted awns, except in the cultivated forms when 

 the awns are straight or lacldhg. Annual grasses with flat leaves 

 and spikelets in large loose panicles. 



1. A. f&tua, L. Wild Oat. 



Stem 1-3 ft. high, simple, erect, smooth ; sheaths sometimes roughened 

 towards the top ; spikelets 2— 1-flowered ; flowering scales covered with stiff 

 brown hairs ; awn long and twisted. A troublesome annual weed in culti- 

 vated fields. 



XI. CYPERACE.ffi (Sedge Family). 



Grass-like or rush-like herbs with solid stems; stem leaves, when 

 present, 3-ranked, with closed sheaths; flowers in spikes each in the 

 axil of a bract, and destitute of perianth, except in some cases a 

 few bristles; style 2-cleft; ovary 1 -celled; fruit an achene. 



1. SCIRPUS. Bulrush. 



Spikelets few or many-flowered, solitary, or in terminal clusters 

 surmounted by an involucre of one-several bracts, which often 

 appear as a withered continuation of the stem ; perianth of a few 

 bristles; stems sheathed at the base, but blades of leaves not always 

 appearing. 



1. S. validus, Vahl. Great Buleush. 



Stem 2-8 ft. high, stout, springing from a strong scaly rootstock; sheaths 

 at the base of the stem sof t,'not green. A very large rush, common around the 

 edges .of lakes and deep ponds. Man.-Alta. 



2. S. rubrotfnctus, Fernald. 



Not so stout as the preceding, 1-3 ft. high; upper sheaths green, leaf 

 blades broadly linear, the upper rising above the flower spike; sheaths 

 mostly red-tinted at the base. Marshy places, Man.-Altar 



3. S. occidetitalis, (Wats') Chase. 



Similar to S. validus, but stems firmer and darker green; bastJ sheaths 

 firmer; flower bracts spotted with red and viscid at the top. Edges of 

 lakes, Man.-Alta. 



2. CAREX. Sedge. 



Perennial grass-like herbs with mostly 3-ranked leaves and tri- 

 angular stems; flowers unisexual, the staminate and pistillate in 

 separate spikes or different parts of the same spike, the staminate 

 consisting of 3 stamens in the axil of a bract, the pistillate of a single 

 pistil with a 2 or 3-parted style developing into an achene. A 



