222 TJniversity of California Publications in Botany [Vol. 6 



quite closely restricted to the neighborhood of a single genus or species 

 of the higher plants. The Boleti putrefy very soon after reaching 

 maturity, usually within two or three days after they first appear above 

 the ground, especially if the weather be moist or wet. This putrefac- 

 tion is usually hastened by the attacks of certain insect larvae to which 

 these plants are particularly subject. The tendency to rapid putre- 

 faction makes their collection and preservation a somewhat difficult 

 matter. The difficulty of collection is increased by the fact that the 

 fruiting bodies of most of our Californian species appear only after 

 the first rains of the season and then are not found again until the 

 following year, being present only in the form of the inconspicuous 

 white or yellowish mycelium. 



The Boleti are often brilliantly colored in shades of red, brown 

 or yellow. The colors, however, are seldom retained to any exact 

 degree in herbarium specimens. Both poisonous and edible species 

 are found among the Boletaceae, but these plants conform even less 

 than do the Agaricaceae to any rules which one may follow to avoid 

 those which are poisonous. 



History 



In looking through the literature we find a considerable number 

 of proposed classifications for the Boletaceae. However, there are but 

 few of these systems of classification which have had any marked 

 effect upon the study of this group in America. 



Turning back to Fries, from whom, by authority of the third Brus- 

 sels Congress in 1910, our system of nomenclature has its beginning, 

 we find in the 8y sterna Mycologicum (1821) that he considers Boletus 

 a genus of the pileate Hymenomycetes of equal rank with Polyporus, 

 Agaricus, etc. In this work the genus Boletus is divided into four 

 subdivisions based upon the presence or absence of a ring, color of the 

 spores, etc., and contains some twenty species, together with several 

 varieties and forms. Fries later revised his classification, and we find 

 in Epicrisis Systematis Mycologici (1836) that he places the Boleti 

 under the family Polyporaceae. He furthermore divides them into 

 seven subdivisions. In this latter work Fries lists, in all, about sixty 

 species. 



Later writers, have as a rule, followed the classification of Fries 

 very closely. 'I'he divisions and subdivisions proposed by him have 

 been treated variously, ])ut in this country the subdivisions made by 

 Fries have been largely followed up to the time of IMurrill. 



