( reneral ( lonsiderations 



MACROSCOPIC CI I \i;\( ITERS 



PlLEUS 



Color — Color has assumed an importance in the classification of 



Hygrophorus at the levels oi subsection and below since the time oi 



Fries and is reflected in the names used lor subgenera .md series in the 

 present work. It is thus important to have accurate data on color and a 

 consistent nomenclature for it. To accomplish this we have used Ridg- 

 wav (1912). All who have used this volume are aware that it is out of 

 print and not easy to acquire; moreover, when it is available, the prob- 

 lem of matching colors is at times difficult. In addition, when attempt- 

 ing to match colors in the gray series especially, one may find this work 

 less than satisfactory. However, it was the best available when we 

 started our studies. 



Color, in Hygrophorus, is caused chiefly by pigments dissolved in 

 the cell sap and to a lesser extent by incrustations on, or pigment in, 

 the cell wall. These pigments have a tendency to be broken down by 

 intense light so that it is not at all uncommon to find a species with a 

 red pileus bleaching out to orange and finally to yellow. In addition to 

 bleaching there is the usual change from a moist to a dry and faded 

 condition which is covered under the term hygrophanous; this situa- 

 tion applies particularly to the section Humidicutis. It is verj impor- 

 tant to note the colors of fresh young caps, mature ones, old ones, and 

 faded ones in ascertaining the color range of a given species. In //. 

 psittacinus for instance, the young caps are parrot green at first, fade 

 to yellow, and become pinkish-vinaceous in age or on drying. The best 

 way to learn about the color range of any species is to observe it when 

 the species is fruiting prolificacy and when fruiting bodies in all stages 

 of development are present. 



In addition to ascertaining the color range ol a species b\ obsen a 

 tion of prolific fruitings, the problem in Hygrophorus is further compli- 

 cated by albinism, or at least white forms of a species which, from field 

 data, appear genetically constant. Such a situation is illustrated by the 

 whitish variant of H. lactus. It is at times difficult in species, such as 

 H. nitidus, to be sure one has a Faded specimen or a white variant. 



Color changes on bruising which result in oxidation caused by 



7 



