174 THE AGARICACEAE OP MICHIGAN 



ceraceus &s obovate with an obscure constriction in the middle, and 

 says they vary characteristically in this genus to reniforni, irreg- 

 ular, etc. I am quite certain that the spores are often quite irreg- 

 ular, angular, etc., when immature, but have a regular outline when 

 mature, although they often tend to be slightly thicker at one end in 

 a number of species. In most species they appear granular- 

 punctate, and usually have a transparent spot on one side, as if 

 perforated. Between most of our species there is not much dif- 

 ference in spore-size, but sufficient difference to be of diagnostic 

 value. The spores are white in mass, and hyaline under the micro- 

 scope. The BASIDIA are quite characteristic within the genus; 

 they are long and slender, tapering to a narrow stalk. They 

 are said to be often 2-spored. CYSTIDIA are not present in 

 the subgenus Limacium, but occur in some of the species of the 

 other subgenera. The ODOR is not marked in any of our species. 

 Several European species are said to have a characteristic odor ; for 

 example: in H. cossus Fr. it is disagreeable, like that of a kind of 

 moth; in H. nitratus Fr. it is strongly alkaline; in H. agathosmus 

 Fr., like oil of bitter almonds. The TASTE is usually mild, and 

 most of them are to be classed among our best edible mushrooms. 

 The HABITAT varies. They grow on the ground, usually in moist 

 or wet situations, in woods, copses, fields and pastures, although in 

 our climate they develop mostly in shaded places. Some appear in 

 early summer, and others are found only in late fall — some species 

 never develop till after the frosts appear. H. hypothejus (Eicken, 

 Blatterpilze) is said to occur only after the first frost. H. 

 speciosus is found, often in good condition, as late as December 

 first. 



The genus is divided into three subgenera, fundamentally limited 

 by the structure of the gill-trama: 



I. Limacium (Hygrophorus proper). 



II. Camarophyllus. 



III. Hygrocybe. 



These three subgenera are raised by some authors to the rank of 

 genera, and from a scientific standpoint should be so considered. 

 But for practical purposes the old arrangement seems better. 



The key includes all species which are likely to be found within 

 the limits of state. 



