need to keep this point in mind when matching a plant under con- 

 sideration with the illustrations in the key. A plant in question may 

 be a species somewhat or quite unlike the one shown. 



The generic names used in the key are those of long-standing and 

 the ones to be found in floras and handbooks the world over. In a 

 few instances the names have been reduced to synonymy by special- 

 ists who have critically examined the old taxonomic literature for long- 

 forgotten synonymies. The advanced student is urged to look into the 

 writings of specialists if he wishes to adopt the recent taxonomic 

 terminologies. 



East Lansing, Michigan 

 August 1, 1954 



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We first met Doctor Prescott when he was working on the Algae of 

 Iowa as a graduate student at our State University. We've had some 

 pleasant correspondence through the years since then and now it is a 

 pleasure to include the results of his years of study in our Pictured-Key 

 Nature Series. 



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I 



H. E. JAQUES 



Editor 



