28 BULLETIN 1053, U. S. DEPARTMENT OF AGRICULTURE. 
normal conditions of growth, and their formation is independent of 
environmental conditions. They germinate immediately and nor- 
mally, are formed in loose dustlike masses, and are easily removed. 
The former he considers a facultative transition form and the lat- 
ter a true propagative form. 
Hotson in two papers (22 and 23) extended and summarized our 
knowledge of bulbils and similar propagative forms, and added the 
finding of bulbils in a few basidiomycetes. Learn (28) , in his cul- 
tures of Pleurotus ostreatus, noted the formation of new mycelial 
growths at the base of wood-block cultures below blocks bearing 
oidia. This suggested the shedding of these oidia from above. Weir 
(62) noted a Ptychogaster form in connection with Trametes 
suaveolens growing naturally, and he remarks that in the damp 
woods of Idaho there are many abnormal polyporoid forms, some 
of them conidial. In Fomes officinalis, Faull (18) found chlamydo- 
spores not only in cultures but also in the crust of the sporophores. 
The writer has found the chlamydospores of this fungus on rotting 
wood in nature (55). Hiley (20) reviewed the status of the conidia 
of Fomes annosus. 
REFERENCES TO THE OCCURRENCE OF SECONDARY SPORES IN NATURE. 
The references to secondary spores occurring in nature are quite 
numerous. Perhaps the least understood of the fungi producing 
secondary spores are the Ptychogasters, which are considered ab- 
normal conidial or chlamydospore fructifications of the polyspores. 
Observations on the Ptychogasters occur chiefly in the older litera- 
ture, and reference may be had to Boudier (3 and 4), De Seynes (50, 
51, 52, 53, 54), Richon (48), Ludwig (30), Patouillard (42 'and 43), 
Brefeld (5), and Weir (62). Then there are the spores reported as 
conidia, called "wet- weather spores" by Lyman (31, p. 135), who 
said that until these spores had been more thoroughly investigated 
their nature must be regarded " as uncertain and their occasional 
production as of doubtful importance to the fungus." (Cf. Patouil- 
lard, 41 <> 44, 46 \ Eichelbaum, 11 ; and Massee, 33.) Of the references 
to secondary spores in nature the status of which is more certain, 
we might mention the following: Chlamydospores on the hairs of the 
stipe of Pleurotus ostreatus (Patouillard. 39) and in the hymenium 
(Matruchot, 34) ; chlamydospores in groups or singly in Trametes 
rubescens (Daedalea confragosa) (Patouillard, 40) ; chlamydospores 
in fruit bodies of Polyporus sulfureus (De Seynes, 50, 51) ; conidia 
(chlamydospores according to Lyman, 31, p. 136) in the hymenium 
of Uydnum coralloides (De Seynes, 53) ; terminal chlamydospores 
in Fistulina hepatica (De Seynes, 50) ; chlamydospores on and in the 
pileus of Nyctalis asterophora and N. parasitica and conidia of Fomes 
