Kauffman : The genus Cortinarius 317 



genus, it will be necessary to point out a few matters relating to 

 their collection and study. It is sometimes desirable to send away 

 one's specimens for identification, and a lack of certain observations 



i 



that should have been made in the field may prevent any one from 

 giving them much attention. 



It is absolutely useless to pick up an old, dried specimen of 

 Cortinarius, and ask any one to recognize it. Once in a while 

 some easily known plant may be recognized in that way, but in 

 the majority of cases old plants of different species look so much 

 alike that it is mere guessing to say anything about them. The 



4 



first thing to remember is that young, unexpanded plants must be 

 examined as \vell as mature ones. Next a careful description 

 must be made, zvitJi special reference to the difference in the color of 

 the gills in the yottng and old plants. Then a similar compari- 

 son of the color of pileus and stem ; and then a search for an an- 

 nulus or universal veil, and its character. Finally a careful test 

 of the pileus and stem for gluten or viscidity. (One must remem- 

 ber that old, dry plants may lose this character.) These points 

 are absolutely essential. In addition to the above, the following 

 characters are often useful : the shape of the pileus ; the size of the 

 parts ; the smoothness of the surface of pileus and stem ; the 

 character of the zA%^ of the gills ; the nature of the bulbous base 

 of the stem ; the appearance of the flesh. In fact, the notes can- 



first. 



proinded they contain the essential facts 



Species 



In working over the material, it was found that the chief diffi- 

 culty lay in the lack of an extensive key to the American species. 

 It is true that Professor Earle * has compiled one from the descrip- 

 tions of the authors ; and although his key sometimes gave me a 

 clue to a species, it also led me astray. This is not so much a 

 reflection on the key^ — which is admittedly a compilation — it 

 rather shows how unsatisfactory are studies which are made from 

 the descriptions alone. The key which is here presented, although 

 worked out and tested on fresh plants alone, must necessarily have 

 many shortcomings. The possibility of mistaking descriptions of 

 species, especially of European origin, is great. Photographs and 



Torreya 2 : 169, iSo. 1 902. 



