CYPERACE^ 173 



straight, stem trigonous ; peat-bogs, frequent. E. Scheuch- 

 zeri, Hoppe ; heads dark grey, perianth-bristles, straight, 

 stem cyHndrical ; high, frequent. 



6. Rhynchospora, Vahl. 



Flowers unisexual or bisexual; spikelets terete, in 

 axillary and terminal panicles or corymbs ; bristles 6 or 

 more. 



R. alba, Vahl ; spikelets white, stamens 2 ; R, fusca, 

 R. and S. ; spikelets dark brown, stamens 3 ; both in bogs, 

 frequent. 



7. Cladium, R. Br. 



Flowers mostly bisexual ; bristles o ; spikelets in 

 panicles or cymes ; leaves rigid, glaucous. 



C, Mariscus, Br. {germanicmn, Schrad.); stem 2-3 

 ft., leaves denticulate, with very sharp edges and keel; 

 marshes ; Switzerland, Jura, Pyrenees ; not common. 



8. SCHCENUS, L. 



Spikelets in compressed terminal bracteate heads; 

 flowers very few, bisexual; bristles 1-6; stamens 3. 



vS. nigricans, L. ; stem 12-18 in., spikelets 5-10, 

 blackish-brown ; 5. ferrugineus, L. ; stem 6-12 in., 

 spikelets 2-3, rusty-brown ; both frequent in bogs. 



9. Elyna, Schrad. 



Spikelets 2-flowered in a terminal spike ; each flower 

 with a large scale-like bract at its base, unisexual. 



E. spicata, Schrad. (Bellardi, Degl.); leaves semi- 



