262 University of California Publications in Botany [Vol. 6 



In the investigation of our Californian plants there have been 

 found, as has been brought out in the detailed description, important 

 differences in the histology as well as in the morphology of plants 

 referred to the same species. These differences appear to be greater 

 than can be explained merely by variations due to habitat, difference 

 of season, or mere individual variation. In several of the forms con- 

 sidered, plants have been found from widely separated localities ex- 

 hibiting the same morphological and histological differences and plain- 

 ly to be referred to the same form. 



In the comparison of our Californian plants with plants from the 

 Eastern United States seemingly important differences in the histology 

 and morphology have been observed. In this ca.se, however, it is im- 

 possible to say how characteristic the structures seen in the plants 

 from the Eastern United States may be, since in each case the material 

 from the East was limited to a single individual. 



In view of the limited amount of material ob.served in many of the 

 Californian plants and in all the eastern plants, I have preferred to 

 arrange the species and the forms under the species to the species to 

 which they were referred by Dr. W. A. Murrill. It seems probable, 

 however, that a more extensive investigation over a longer period and 

 with more abundant material, both of individuals and of species and 

 forms, Eastern and European as well as Californian, may indicate that 

 certain of our Californian plants which have been discussed in this 

 paper as forms should be elevated to specific rank. It is probable 

 that some, if not all, of the Californian plants referred to, may differ 

 sufficiently from the Eastern plants now referred to the same species, 

 to cause their being placed ultimately under separate species. 



There are several lines, as indicated above, along which future in- 

 vestigation may lead to valuable increase of our knowledge of the 

 Boletaceae. As has been stated previously in this paper, a veil has 

 been found in at least two forms of Ceriomyces referred to two 

 different species. In both these species the presence of a veil has not 

 been previously described. It is true that in both causes the veil is 

 present only in the younger individuals, and later entirely disappears, 

 being persistent neither as an annulus nor as a fringe on the margin 

 of the pileus, but since in other species of Ceriomyces, cf. C. Zelleri 

 (Zeller, 1914), there is no evidence of a veil at any time during the 

 development of the sporophore, a very important line of cleavage is 

 indicated in this genus. Those forms with a veil in the early stages 



