

FUNGI OF IMPORTANCE IN THE DECAY OF TIMBERS. 11 



in a photographic plate box with a slit 5 millimeters wide cut in one 

 of the narrow sides. The box was set up with the slides inside, the 

 slit toward an east window. In the first test the cells were inocu- 

 lated at night and examined in 24 hours. In the second the inocu- 

 lations were made in the morning and examined in 24 hours. In 

 neither set did the germ tubes of any of the four species, Lenzites 

 sepiaria, L. trabea, Trametes seriaZis, Lentinus lepideus, show any 

 phototropic response. The tubes pushed out of the ends of the 

 swollen spores as usual, and their subsequent course was as irregular 

 as in the dark or in diffused light, where checks were placed. 



RETENTION OF THE VIABILITY OF THE BASIMOSPORES. 



Falck (IS, pp. 99~100) expressed the opinion that in nature the 

 length of time the spores of wood-destroying fungi could retain 

 their viability was a matter of little moment, inasmuch as most of 

 them had the ability at least to hold over the longest period of 

 drought. Eumbold (49, p. 102) found that 0.25 per cent of the 

 spores of Coniophora cerebella germinated after one year and six 

 months under laboratory conditions. Falck (15, p. 100) reported 

 that the spores of Lenzites sepiaria 6 months old germinated like 

 fresh spores, but from that time there was a steady decrease in the 

 percentage of germination. In a year and seven months only a very 

 few germinated, and none in two years. The spores of Merulius 

 lacrymans he found (16, p. 234) to be longer lived. Spores 1 year 

 old germinated normally ; after three years 25 per cent germinated ; 

 and after five or six years spores sprayed with 2 per cent malic 

 acid, dried immediately, and then put in a moist chamber at 15° 

 C. gave some germination. Rhoads (47, p. 70) showed that the 

 spores of Poly poms pargamenus kept on waxed paper in a desk 

 in a warm room remained viable for 10 months, but not for 12. 

 At the end of that time there was swelling, but no germination. 



The question as to the maximum period of retention of vitality re- 

 solves itself into how best to preserve spores under laboratory condi- 

 t ions. It has been shown by Falck (15, p. 100) and Moller (36, p. 38) 

 that spores are best preserved when taken dry and kept dry, and that 

 spores in a moist atmosphere soon deteriorate. Thick prints also 

 undoubtedly keep better than thin ones. Just what combination 

 of dryness and temperature is more favorable for prolonging the 

 life of the spores is not certain. The writer has kept spores best in 

 an ice box, where the temperature, was found to be 12° to 15° C. 

 and the relative humidity 40 to 45 per cent. A very humid at- 

 mosphere is harmful, as are also very dry conditions at higher tem- 

 peratures. Whether very dry and cool conditions would be better 

 than a moderate amount of moisture in the air at the same tem- 

 perature is not known. 



