INTRODUCTION. 



Since the issue of my " Studies and Illustrations of Mushrooms," 

 as Bulletins 138 and 168 of the Cornell University Agricultural Ex- 

 periment Station, there have been so many inquiries for them and 

 for literature dealing with a larger number of species, it seemed 

 desirable to publish in book form a selection from the number of illus- 

 trations of these plants which 1 have accumulated during the past six 

 or seven years. The selection has been made of those species repre- 

 senting the more important genera, and also for the purpose of illus- 

 trating, as far as possible, all the genera of agarics found in the United 

 States. This has been accomplished except in a few cases of the 

 more unimportant ones. There have been added, also, illustrative 

 genera and species of all the other orders of the higher fungi, in 

 which are included many of the edible forms. 



The photographs have been made with great care after consider- 

 able experience in determining the best means for reproducing 

 individual, specific, and generic characters, so important and difficult 

 to preserve in these plants, and so impossible in many cases to 

 accurately portray by former methods of illustration. 



One is often asked the question : " How do you tell the mush- 

 rooms from the toadstools ? " This implies that mushrooms are edible 

 and that toadstools are poisonous, and this belief is very widespread 

 in the public mind. The fact is that many of the toadstools are 

 edible, the common belief that all of them are poisonous being due 

 to unfamiliarity with the plants or their characteristics. 



Some apply the term mushroom to a single species, the one in 

 cultivation, and which grows also in fields (Agaricus campestris}, 

 and call all others toadstools. It is becoming customary with some 

 students to apply the term mushroom to the entire group of higher 

 fungi to which the mushroom belongs (Basidiomycetes), and toad- 

 stool is regarded as a synonymous term, since there is, strictly 

 speaking, no distinction between a mushroom and a toadstool. 

 There are, then, edible and poisonous mushrooms, or edible and 

 poisonous toadstools, as one chooses to employ the word. 



A more pertinent question to ask is how to distinguish the edible 

 from the poisonous mushrooms. There is no single test or criterion, 

 like the "silver spoon" test, or the criterion of a scaly cap, or 

 the presence of a "poison cup" or "death cup," which will serve 



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