LYMAN: STUDIES OF HYMENOMYCETES. 
145 
Of the five classes mentioned above, the fourth seems to be of the 
greatest importance in the present discussion of polymorphism. Co- 
nidia of the first class are characteristic of the Protobasidiomycetes, and 
the Hymenomycetes which possess them, Paehysterigma and Muei- 
porus, are in many ways allied to the Protobasidiomycetes; hence this 
method of germination of the basidiospore is interesting as indicating 
possible affinities of the genera in question. Brefeld reports this 
method of germination also in Radulum laetum, but it seems doubtful 
whether this is the normal method in this species. The spores of the 
second class, being produced by modified basidia, are intrinsically 
basidiospores and not conidia; hence they belong more properly to the 
realm of teratology and should not be given great weight in this dis¬ 
cussion of polymorphism. The third class of spores may also come in 
the same category as the second, and even if it be shown that they are 
true secondary spores and not modified basidiospores, their occasional 
production as the result of certain unfavorable conditions of growth, 
and the apparent absence of power of germination in most cases, 
would seem to indicate that they are neither normal nor important 
factors in the life histories of the fungi concerned. 
The more highly differentiated spores of the fourth and fifth classes 
are of greatest importance in the present discussion. Unfortunately, 
the basidiomycetous nature of spores of the fifth class needs to be 
demonstrated by further study; hence there remains only the fourth 
class, viz., the well differentiated conidia found in the genus Tomen- 
tella and in Polyporus annosus. The exact status of the conidia of 
Tomentella has not been proven by culture study, but Brefeld’s testi¬ 
mony as to their connection with the basidiosporic fungus seems to have 
been accepted and confirmed by other writers. The author of this 
paper has been so fortunate as to obtain fresh specimens of Polyporus 
annosus, and the mycelia from the germinating basidiospores pro¬ 
duce in abundance the interesting conidia described by Brefeld. The 
latter’s observations upon this species were confirmed in all essential 
particulars. 
Thus, in the light of our present knowledge, it appears, that in the 
great majority of Hymenomycetes there are no secondary spores; that 
where present, these spores usually take the form of mycelial oidia as 
in many of the Agaricaceae, or of chlamydospores produced upon or 
within the basidio-fructification as in certain of the Polyporaceae; 
that conidia of a more of less doubtful character are reported in a 
