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IOWA ACADEMY OF S^IENC^E Vol. XXV, 1918 



usually distinguished at the junction of the leaf and sheath by 

 the color; the auricles are appendages projecting from the col- 

 lar or top of sheath. These together with the rhizomes form 

 very important basic characters for identification of grasses. 



9. The vascular system is represented by nerves, in some 

 species conspicuous. The arrangement and number of nerves 

 is a character which aids in identification. 



Pig. 140. — Spartina cynosuroides. Slough Grass. A, ciliate ligule ; B, 

 collar ; C, rhizome ; D, base of old culms, and new shoots and scales ; E, 

 node and scales of rhizome. 



10. The character of the rhizome, blades in the bud, sheath, 

 ligule, collar, and auricles may furnish a basis for further study 

 of the identification of perennial grasses by their vegetative 

 organs. 



NOTE. Acknowledgment is due to Dr. L. H. Pammel under whose 

 direction the work was begun, also to Miss King, Miss Hayden, and 

 Mr. L. W. Durrell for helpful suggestions in regard to drawings. 



