Kauffman : The genus Cortinarius 313 



times its width. An apiculus, or projection, is usually noticeable 

 and represents the point where the spore is attached to the 

 sterigma. 



The spores also vary in the structure of the epispore. This is 

 often covered with spiny or tubercular processes ; in other cases 

 the spores are quite smooth. In using this as a specific character 

 one must never lose sight of the fact that when young all spores 

 are smooth. It is therefore necessary to make sure that the spores 

 referred to are mature. 



The size of the spores is, in my opinion, of much greater value 

 for diagnostic purposes, than has hitherto been recognized. There 



is no doubt that the size of the spores of a single individual varies, 



Y 



and that it varies when there is every evidence that the spores are 

 mature. But that they vary within limits, w^hich are sufficiently 

 constant, any one can determine for himself. One need only tate 

 measurements of a great many spores from a number of individ- 

 uals of an easily recognized species (it is hoped that there are a few 

 such species). One finds, indeed, a certain number of abnormal 

 spores which are larger or smaller than the majority. But these 

 should not be taken into account. It is time that we look more 



I 



closely into the microscopical characters of these plants, and it is 

 a pleasure to read Mr. Massee's discussion of this point in his 

 recent monograph of the genus Tnocybe.'^ 



The spores of the genus Cortinarius have in all cases examined 

 been found constant within limits. These limits are at times re- 

 markably narrow, at other times just as remarkably wide. For 

 example, a plant which has usually been called C, alboviolaceus 

 Fr. in this country, has spores, which at maturity, are from 6.5 to 

 9.5 /^ long, — it is meant by this that the average spores found in 

 the field of the microscope in several mounts, and of as near the 

 mature color as possible, are within these Hmits. A few may be 

 longer, a number of younger, paler ones are shorter, but spores 

 from this same species always show this same variability. On the 

 other hand, C, ammlafiis Pk. has rather constant spores, somewhat 

 spheroid, y p, long by 6.5/i broad. In this case a single figure is 

 sufficient to denote the length or breadth. 



Several species have been studied in prepared sections, in which 



*Ann. Bot. 18 : 



459 



