8 



7a. Spikes subtended by long conspicuous leaves which greatly ex- 

 ceed the flower clusters 8. 

 7b. Spikes not conspicuously exceeded by the bract-like leaves 10. 



8a. Spikes in a dense head-like cluster, white-woolly at maturity 



Cotton Grass, Eriophorum Yirginicum. 



8b. Spikes not in dense heads, nor white-woolly at maturity 9. 



9a. Perennial by a creeping rootstock. Xut Grass, Cyperus esculentus. 

 9b. Perennial by hard basal corms Cyperus, Cyperus strigosus. 



lOa. Bracts of the spike chestnut-brown 



Twig Rush, Cladium mariscoides. 



lOb. Bracts of the -spike green or straw-color (Sedge) 11. 



lla. Spikes. 3 8, separate Sedge, Carex straminea. 



lib. Spikes very numerous and densely crowded 



Sedge, Carex \ulpinoidea. 

 12a. Achenes flattened Sedge, Carex crinita. 



12b. Achenes 3-angled 13. 



13a. Perigynium tipped with a sharp straight 2-toothed beak 14. 

 13b. Perigynium with a short soft beak 17. 



14a. Perigynium thin and papery, loosely enclosing the achene 



15. 

 14b. Perigynium firm, closely enclosing the achene 16. 



15a. Perigynium less than 1 cm. long Sedge, Carex hystericina. 



15b. Perigynium. more than 1 cm. long Sedge, Carex lupiilina, 



16a. Perigynium smooth Sedge, Carex riparia. 



16b. Perigynium hairy Sedge, Carex filiformis. 



17a. Beak of the perigynium bent abruptly to one side 



Sedge, Carex laxiflora. 

 17b. Beak of the perigynium straight Sedge, Carex pennsylyanica. 



ARACEAE, the Arum Family 



Individual flowers small, but crowded on a fleshy spadix to form 

 a conspicuous spike, usually surrounded by a green or colored spathe. 



la. Leaves compound 2. 

 Ib. Leaves simple 3. 



2a. Leaflets 3, spathe pale green or purple (3 6 dm. high; 



spring) Indian Turnip, Arisaema triphyllum. 



2b. Leaflets 7 11; spathe green; spadix long and slender (3 8 



dm. high; late spring) Dragon Root, Arisaema dracontium. 



3a. Leaves linear, sword-shape; spathe none (5 15 dm. high; early 

 summer) Sweet Flag, Acorus calamus. 



3b. Leaves broader than linear; spathe present 4. 



4a. Flower clusters partly underground, appearing in earliest 

 spring Skunk Cabbage, Symplocarpus foetidus. 



4b. Flower clusters peduncled, in early summer 5. 



