KEY TO THE GRASSES 



In the illustrated description of the grasses the species follow 

 one another in the order given in modern botanical works, such 

 arrangement being based on the characteristics of spikelet and 

 flower. Technical descriptions are given of the more common 

 species of a genus. The general descriptions include other species 

 and note their chief characteristics. 



The key, being intended for use in the field, is based on the 

 characteristic form of the flowering-head. Somewhat arbitrarily 

 the terms used in describing the form of the infloresence have been 

 restricted to spike and panicle, omitting the word raceme and, 

 instead, using the term spike to include any flowering-head in 

 which the spikelets have the appearance of being placed directly 

 on the main axis of inflorescence. Thus, the apparent form of the 

 flowering-head is noted and that of Timothy is given as a spike, 

 since it has that appearance, although it is, in fact, a spike-like 

 panicle; the spike-like racemes of Bur-grass, Gama Grass, and 

 others are given as spikes. 



The generic and specific names are those given in Gray's "New 

 Manual of Botany" (Seventh Edition). 



In the key and the technical description in the following pages 

 the measurements are in feet, inches, and lines. 



The symbol ' is used after figures to indicate inches, and the 

 symbol " is used to indicate lines. A line is the twelfth part of an 

 inch, hence 3" equal one quarter of an inch, 8" equal two thirds 

 of an inch, etc. 



ARTIFICIAL KEY 



Based on the more noticeable characteristics of the inflores- 

 cence: 



Inflorescence consisting of spikes or spike-like panicles — I. 



Inflorescence consisting of short panicles, one to four inches 

 in length — II. 



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