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 

 chlamydospores (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 Collybia 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 chlamydospores 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 chlamydospores appearing naturally was not tested. 

 The finding of chlamydospores 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 f 9) and Falck 

 (15) and chlamydospores also by Falck. Long and Harsch (29) 

 reported the occurrence of chlamydospores in cultures of Lentinus 

 lepideus. As far as the writer knows, the chlamydospores formed 

 by Trametes serialis have not been reported, although Mez (35, 

 p. 116) mentioned a brown corky Ptychogaster form of this species 



