30 BULLETIN 1053, U. S. DEPARTMENT OF AGRICULTURE. 
the basidiospores of the dry-rot fungus are difficult to germinate and 
may have low germinability in nature. He further states that the 
ehlamydospores (asserted to be oidia by Falck) if found outside arti- 
ficial cultures would probably contribute to the spread of the fungus. 
Falck (16, p. 132), on the other hand, maintained that the oidia 
of Merulius were not true propagation organs. The same writer in 
1902 (13, p. 319) remarked that insects must spread the oidia of 
Hypholoma and Pholiota, which are formed in abundance on firm 
substrates. He believed that the formation of oidia on blocks infected 
with Collyhia velutipes placed in moist moss illustrated the im- 
portance of these spores in nature. These oidia were formed in col- 
onies in the air, undoubtedly for insect dissemination, he avers, but 
he doubts whether they could be detached by the wind. Falck (15. 
p. 144) also maintained that the tertiary oidia of Lenzites sepiaria 
" doubtless play an important part as organs of propagation, inas- 
much as the spores might easily be carried away by animals in 
creases of their bodies, etc. A somewhat rough shaking loosens single 
end-spores from one another, and these can easily be collected on 
slides held beneath.*' 
Munch (37, p. 577), however, believes that oidia do not possess in 
nature the great significance for the spread of the fungus which 
Falck claimed for them. He observes that the conditions of oidia 
formation are not clear, that their formation in nature is not possible 
in cases that have come to his attention, because of the inability of the 
fungus to get to the air, and that direct observations of oidia in 
nature are lacking. He asserts that this form of reproduction is 
merely a makeshift at best and not a normal reproductive form. 
Faull (18, p. 201), as mentioned above, found ehlamydospores in 
the crust of sporophores of Fomes officinalis and expressed the belief 
that they are a means of reproducing the fungus, although the 
viability of these ehlamydospores appearing naturally was not tested. 
The finding of ehlamydospores of this fungus in nature by the 
writer (55) has suggested their importance in the spread of the 
fungus. 
OCCURRENCE OF SECONDARY SPORES IN CULTURES OF THE 
FUNGI STUDIED. 
Of the five fungi used by the writer in these studies, secondary 
spores have been found in four. Oidia have been previously re- 
ported in cultures of Lenzites sepiaria by Rumbold (J/9) and Falck 
(15) and ehlamydospores also by Falek. Long and Harsch (20) 
reported the occurrence of ehlamydospores in cultures of Lentinus 
Jepideus. As far as the writer knows, the ehlamydospores formed 
by Trametes serialis have not been reported, although Mez (35, 
p. 116) mentioned a brown corky Ptychogaster form of this species 
