200 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
conidia, at least upon the mycelia, are less common in these families 
than in the Thelephoraceae. 
As a result of his culture studies, Brefeld developed a theory of 
the origin of the Basidiomycetes. He believes that the basidium is 
but a modified conidiophore in which the spores are reduced to the 
fixed number four. The Basidiomycetes, in his opinion, are not of 
common ancestry, but originated at several points where the basidium 
developed from the conidiophore. Pilacre, Tomentella, and Polyporus 
annosus are plants in which the ancestral conidiophore is still pre¬ 
served in connection with the derived basidium. 
If Brefeld is correct in assuming that the basidium of Polyporus 
annosus is derived from the Oedocephalum-like conidiophores of 
that species, then the same relation must exist between the basidium 
and conidiophore of Corticium effuscatum, although here the basidio- 
spores and conidia are more dissimilar than they are in the former 
species. In Corticium roseo-pallens the conidia and basidiospores 
differ only in length, but the low conidiophores do not much resemble 
the basidia, and the successive development of the conidia is another 
point of difference. However, some remote relation between conidio¬ 
phore and basidium might be advocated in this species also. 
This theory of Brefeld’s, based largely upon external resemblance 
of the organs in question, is open to serious objections, and leaves 
many questions unanswered. It is not the writer’s plan, however, 
to discuss this topic further, for the many interesting and important 
questions which arise concerning the nature of the Basidiomycetes 
lie entirely beyond the scope of the present culture study. 
Summary. 
(1) The basidiospores of about seventy-five species of Polyporaceae, 
Hydnaceae, and Thelephoraceae (the majority belonging to the last 
group) were germinated and grown in pure cultures; about 40% of 
these possess some secondary method of reproduction, usually mycelial 
oidia or chlamydospores. 
(2) Oidia were not found among the Thelephoraceae and Hydna¬ 
ceae, but were produced by one half of the species of Polyporaceae 
studied. Hence the writer’s results confirm those of previous observers, 
that oidia are common upon the mycelia in the Polyporaceae and 
