12 GENERAL CONSIDERATIONS 



blue, green, gray, brown, or various shades of these. In the Rubentes of 

 section Hygrophorus they become reddish-spotted to entirely dark vi- 

 naceous red. In H. paludosus Peck they become spotted with green or 

 olive. In most species the gills are pale at first and merely develop a 

 flush of the color of the pileus, as in H. pudorinus. If brilliant when 

 young, the gill color tends to fade out in age, but in H. marginatus var. 

 marginatus the lamellae are bright orange, and this color usually per- 

 sists, at least along the edges, long after the pileus has faded. Few spe- 

 cies in Hygrophorus, however, regularly have the gill edges a different 

 color than the faces, a condition referred to as marginate, and which 

 characterizes a number of species in the related genus Mycena. 



Color changes which occur from injury are as important on the 

 gills as on the pileus and have already been discussed. 



Stipe 



The context of the stipe and pileus in Hygrophorus are continuous, 

 and therefore the one organ is not easily separated from the other. The 

 stipe is typically central in its attachment to the pileus, but occasional 

 specimens with an eccentric stipe do occur in some species, H. cama- 

 rophyllus, for instance. Characteristically it is solid or stuffed solid, the 

 latter description applying when a pith can be distinguished from a 

 cortex. 



The surface features of the stipe are, however, important in the 

 recognition of species. Color and color changes are important here, as 

 they are for the pileus. The stipe may be practically the same color as 

 the pileus, or the apex may be paler. The stipe is likely to be most 

 heavily pigmented in the lower two-thirds of its length, except for the 

 buried base which is likely to be pallid. The stipe may be white at first 

 and become flushed with the color of the pileus later, as in H. pudori- 

 nus. In some there is a tendency for the base to change color to yellow 

 (H. pudorinus) or some other color, and this change may not be in the 

 category of a change due to bruising. We have found that where grow- 

 ing in deep moss, as in variants of H. camarophyllus, the pigment may 

 fail to develop in the stipe causing it to appear pallid. 



The most important color character, however, is that involved in 

 the application of certain chemicals, such as ferrous sulphate, potassium 

 hydroxide, Melzer's reagent, and other chemicals to the surface orna- 

 mentation. This is an area for future investigation as our data are in- 

 complete for most species, but in the tests made to date some striking 

 results have been obtained. In H. pudorinus for instance, the ornamen- 

 tation at the apex of the stipe is instantly yellow to orange in KOH. In 

 certain species, such as H. tephroleucus and H. pustulatus, the orna- 



