76 ELEVENTH REPORT. 



Solitary or gregarious. In coniferous or mixed woods of the northern 

 peninsula. Rare. July, August and September. 



The above description agrees fairly Avell with that of the R. aeruginea 

 found about Stockholm. Fries refers to the gills as shining white (ccmdidae), 

 but the gills of the Swedish plants like ours soon become dingy white and are 

 often discolored in the middle. Their plants grow larger, have a more glabrous 

 pileus, and are more abundant, but are evidently the same species. It is 

 placed among the Fragiles in Hymen. Europ. but it is c^uite firm as a 

 rule, and our specimens were at first referred to R. heterophylla Fr., a 

 species concerning which the European mycologists seem at present to be 

 somewhat uncertain. 



25. RUSSULA OLIVASCENS Fr. 



(The pale olive Russula.) 



Pileus 5-8 cm. broad, rather firm, convex then piano-depressed or umbili- 

 cate, olivaceous on disk, paler on margin, no purple shades present, pruinose, 

 opaque, margin even or at length slightly tubercular-striate, pellicle slightly 

 separable, hardly ever viscid. Flesh white, unchangeable, thin on margin. 

 Gills cream color, medium close, moderately broad, narrowed behind and 

 adnexed, broader in front, thin, few shorter, few forked. Stem 5-7 cm. 

 long, dull white, rather stout, firm, spongy-stuffed, sometimes compressed, 

 subec[ual, sometimes abruptly short attenuate at base, obscurely reticulate. 

 Spores creaiyiy-yellow, subglobose, echinulate, 7-9 micr. Taste mild. Odor 

 none. 



Gregarious. Hemlock and mixed swamp, Sault Ste. Marie, oak and maple 

 woods at Ann Arbor. July. Infrequent. 



This species does not seem to be known to the present Swedish mycolo- 

 gists. The R. olivascens of Persoon is usually joined with R. alutacea. Peck 

 reports our plant from N. Y., and Denniston from Wisconsin. If the color 

 of gills and spores are significant, then our plant is hardly Persoo'n's species 

 and cannot be joined to R. alutacea. Close to the preceding. 



26. Russula sororia Fr. 

 (The sister Russula.) 



Pileus 3-6 cm. broad, rather firm, convex then subexpanded, viscid when 

 moist, margin substriate when mature, pellicle somewhat separable along 

 margin, grey, olivaceous-brown or grayish-brown. Flesh white, unchanged. 

 Gills narrow, subdistant, distinct, white for a time, then discolored, adnate 

 shorter ones intermingled, rarely forked, interspaces venose. Stem 2.5-5 

 cm. long, 1-2 cm. thick, white, not becoming cinereous, short, spongy-stuffed. 

 Spores white. Taste acrid. Odor none. 



Solitary. Woods in southern Michigan. August and September. 



This species used to be placed under i?. consohrina. We have a form with 

 colors much the same, the cap and base of stem rusty-blotched, but gills and 

 spores straw-yellow. It is appended for the present to this species, as 

 its position is uncertain. 



27. Russula consobrina Fr. 



This species has not been reported for the state. It is characterized by 

 its acrid taste, even margin and uniform grayish color on the cap, the flesh 

 of the stem turning cinereous with age and the white spores. 



