FUNGI OF IMPORTANCE IN THE DECAY OF TIMBEES. 9 



Fomes roseus spores germinated most rapidly between 28° and 32° 

 C. (82° and 89° F.), while the percentage was highest between 24° 

 and 32° C. (75° and 89° F.). 



For Lentinus lepideus the largest percentage of germination was 

 between 25° and 28° C. (76° and 82° F.), although 40 per cent ger- 

 minated in 16 hours at both 20° and 32° C. (68° and 89° F.). The 

 percentage for the lower temperatures down to 5° C. (40° F.) was 

 40 to 50 per cent. These spores germinated in 10 hours at 28° C. 

 (82° F.) and in 18 to 20 hours at 24° C. (75° F.). 



Falck (16, p. 258) has suggested that the percentage optimum for 

 germination of basidiospores is to a certain extent a matter of 

 simultaneous germination, and that as the optimum is approached 

 there is a greater number of simultaneously germinating spores. 

 Inasmuch as all the spores do not germinate at the same time, par- 

 ticularly at the lower temperatures, care should be taken to give 

 the viable spores opportunity to germinate. According to Falck, 

 the more favorably situated spores germinate first, but there is also 

 the possibility that the less favorable temperatures affect the proto- 

 plasm of the individual spores differently and thus cause differ- 

 ences in rapidity of germination. In the case of Lentinus lepideus 

 (Table 1) at 5° C. only a small percentage had germinated in 5 

 days, 30 per cent in 8 days, and 40 per cent in 10 days. Care must 

 be taken also that the percentage counts are not made at intervals 

 too great to keep track of what is going on at the lower tempera- 

 tures. Whereas basidiospores of L. lepideus germinated 30 per cent 

 in 8 days and 40 per cent in 10 days at 5° C, in 23 days in the same 

 set of duplicate hanging drops only 22 per cent of living thalli could 

 be counted. The explanation seems to be that of the 40 per cent 

 which had germinated, a certain number of the germinated spores 

 could not stand the low temperature and had died and become in- 

 visible on the agar substrate. 



EFFECT OK LIGHT UPON THE GERMINATION OF THE HASIDIOSPOKES. 



Hoffmann (21. p. 32) found that spores of Agaaricus ownvpestHs 

 germinated sooner in the light than in the dark and that bright sun- 

 light did not hurt the spores of several imperfect fungi and some 

 rusts. Ferguson (19, p. 21) found, however, that the spores of 

 Aga/ricus canvpestrfe would not germinate in direct sunlight or in 

 diffused light in four weeks, even under the special conditions fur- 

 nished by her for the germination of these refractory spores. In the 

 experiments by Bullet (£, pp. '24—20) spores of Daedctlea unicolor 



;ind Srh't'-coph.yll'uni com'iini iw germinated after exposure to direct 

 BUnlight for periods up to eight hours. I >i 1 1 the germination of these 

 was slower than of those kept in the dark", and the percentage of 

 82278 22 2 



