Pileate and Clavate Tribes of Hymenomycetous Fungi. 99 



I am by no means positive as to its correctness in all points. 

 I have probably in some instances confounded analogies with 

 affinities; but they are thrown out at least as hints. It 

 would carry me to greater length than is desirable to state 

 fully the grounds on which they are indicated. My object is 

 principally to call the attention of students to the room which 

 still remains for investigation, even in the field which has 

 been so successfully trod by Fries. Too much attention can- 

 not well be paid to any of his suggestions, to which every my- 

 cologist must acknowledge the deepest obligations. It seems, 

 however, almost impossible that any system can be right in 

 all its parts which is founded on false notions of the struc- 

 ture of the group of highest importance. 



The facts stated above confirm in a striking degree the 

 theory that a quaternary arrangement prevails in Cryptogamic 

 plants. It will be seen from the anomalous cases mentioned 

 above that the spicules have a definite arrangement, even 

 when the number exceeds four. Few facts are more curious 

 than that the number four should prevail when the fructifica- 

 tion consists of spores, and a multiple of four when it is con- 

 tained in asci. 



How far modifications of the form of the sporophores may 

 be found of use in distributing the species of the genus Aga- 

 ricus I am not prepared to state, not having made a series of 

 observations with a view to that especial point. M. Montagne, 

 it appears, is distinctly of opinion that they are of great value, 

 taken in connection with the structure of the inner substance 

 of the gills. Link pointed out nearly thirty years since that 

 an easy distinction is afforded by the nature of the cellular 

 substance between the Russula and Ag. Russula. The sub- 

 ject is one of considerable interest, but of extreme difficulty, 

 and requires for its investigation all the aid that can possibly 

 be afforded by the best instruments and the most dexterous 

 manipulation ; and no attempt at generalization can well be 

 expected to be successful till some hundreds of species have 

 been examined. It cannot be in better hands than in those 

 of the learned French mycologist, the publication of whose 

 memoir we wait for with great anxiety. 



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