MICHIGAN ACADEMY OF SCIENCE. 67 



7. RussuLA DENSiFOLiA Secr. 

 (The close-gilled Riissula.) 



Illustrations: Hard's Mushrooms. 1908. P. 197, Fig. 157. (Probably 

 also Fig. 145.) 

 See remarks on the preceding. It seems to me that this and the R. aclusta 

 are rather close, but a study of the plant in its natural habitat may show 

 more differentiating characters than the descriptions so far indicate. It is 

 a question whether mere color changes like those of this plant are specifically 



important. 



8. RussuLA coMPACTA Frost. 



(The compact Russula.) 



Illustrations: N. Y. State Mus. Bull. 116. PI. 109, Fig. 1-4. 



This is said to differ from R. sordida in the presence of a disagreeable odor 

 when drying, the gills turning reddish-brown when wounded and smoky- 

 brown in drying, the gills are sometimes subdistant, and hence it approaches 

 R. nigricans. It has not been recognized, and seems very close to some of the 

 preceding. 



9. Russula magnifica Pk. 



Illustrations: N. Y. State Mus. Bull. 67. 1903. PI. N. Fig. 1-4. 

 Not yet reported from the state. 



RIGIDAE. (RUSSULA Fr. in part.) 



The pileus is compact and firm, provided with a pellicle which is either 

 closely adnate and manifest or develops more slowly than the flesh beneath 

 and so is broken into areolae or vanishes entirely at maturity, mostly separable 

 on the margin, .sometimes viscid. Gills are forked or entire, .shorter ones 

 occasionally intermingled. 



SECTION A. 



Margin of pileus obtuse, at first convergent at stem. Gills broader an- 

 teriorly. 



9. Russula rubra Fr. 



(The Red Russula.) 



Acrid. The history of this species is very confusing. In Europe, mycolo- 

 gists are not agreed on the plant which belongs here. Romell says that the 

 plant described by Fries under this name is certainly not the plant which is 

 figured in the plates which are deposited in the museum at Stockholm and 

 which Fries approved. Peltereau says that the modern plates and descrip- 

 tions of R. rubra are so confusing and so different from the type that "c'est 

 une vrae tour de Babel." He thinks Quelet's R. rubra is like a R. lepida 

 with a deep color and acrid taste; that Bresadola's has a white stem and. 

 reminds of R. Clusii Quel.; that Romell describes a plant which must be R. 

 lepida as at present known in France, the Swedes seeming to have lost the 

 traditions of the R. rubra of Fries. Peltereau concludes that since there 

 is such confusion the name would better be dropped. Peck gives the following 

 description of a species which he refers to R. rubra Fr., but which I have not 

 yet observed in Michigan. 



"Pileus fleshy, hard, rigid, convex becoming nearly plane or centrally 



