I9i6] Yates: Histology of Califoruian BoJctaceae 261 



SUMMARY 



The general purposes of the studies leading up to this paper, as 

 outlined at the beginning, have been: 



1. To extend so far as possible the knowledge of the species of 

 Boletaceae growing in California, about which there existed at the be- 

 ginning of the work very little, if any, certain information. 



2. To make such a study of the histology of the various species of 

 the Boletaceae as to assist in furthering our knowledge along the two 

 following lines: (1) To determine, as accurately as possible, the de- 

 tails of the individual species; and (2) to compare the histology of 

 different individuals of the same species as well as of individuals re- 

 ferred to different species. 



3. To obtain, if possible, histological characters which might be ap- 

 plied to dried or living specimens to confirm, or to bring into question, 

 determinations made according to general morphological characters. 



The results of this investigation are briefiy summarized below, 

 although it has been found that a much more extensive examination of 

 living material from more widely separated localities, as well as of the 

 type specimens, will be necessary before the problems outlined above 

 can bring forth accurate and explicable results. 



First : we have seen that there were formerly attributed to Cali- 

 fornia some sixteen species of Boletaceae, but not all of these are to 

 be considered so definitely referred as to pass without challenge. In 

 the attempt to extend the knowledge of Californian species of this 

 family there have been fairly certainly found to be some six well- 

 defined species as commonly considered and under three of these it 

 has also been possible to separate out certain definite forms. From 

 Ceriomyces communis, for instance, there have been separated out four 

 forms, from Ceriomyces crassiis two forms, and from SuilleUus East- 

 woodeae two forms, so that altogether we have eleven dift'erent forms, 

 some of which, at least, appear to be entitled to consideration as sep- 

 arate entities. There are doubtless many other forms to be found in 

 California, since Harkness and ]\Ioore credit the Bay region with .some 

 sixteen species, but it is impossible at present to verify their de- 

 terminations. 



In regard to the second object of the study, it has Ixh'u possilile 

 to give, in fair detail, the histology of these different species and forms. 



