8). Germination was usually by a single germ tube 

 that continued growing for more than 24 hours. 

 Excellent germination and germ tube development 

 occurred from about 8°-13° to 23° -28° C, but 

 germination was poor at the extremes of 3° and 33° 

 C.(fig. 12). 



In other tests, telia that had been in storage 

 at 5° to 7° C. for several weeks often produced 

 basidiospores, many of which germinated by forming 

 either secondary basidiospores or short (<10ij) broad 

 germ tubes, rather than by forming normal tubes, 

 which generally reach more than lOOy in 24 hours. 

 Such abnormal types of germination are also seen 



6 8 10 



EXPOSURE TIME 



Figure ll.-Survival of basidiospores after expo- 

 sure to various temperatures and relative 

 humidities, as indicated by subsequent 

 basidiospore germination. 



occasionally in basidiospores cast from field collec- 

 tions of older telia, but not in those cast from fresh 

 young telia. 



100 



8 13 18 23 28 



TEMPERATURE (Degrees Celsius) 



Figure 12.-Germination of basidiospores at sev- 

 eral temperatures after 24 hours' incu- 

 bation. The darker lines are mean curves 

 of the individual trials. 



33 



Table ^.-Influence of incubation time on germination of basidiospores 

 at cool, moderate, and warm temperatures 



Time 

 (hours) 



Germination 



Temperature (degrees C.) 



li 



28 



Mean germ tube length 



Temperature (degrees C.) 



li 



28 



Percent 



Microns 



3 







28 



6 







16 



8 



6 







100 



17 







26 



13 



12 



64 



100 



35 



18 



85 



21 



24 



94 



100 



54 



76 



159 



29 



48 



85 



100 



65 



130 



243 



38 



12 



