62 



Mycologia 



would find favorable conditions for growth'on our native species. 

 It is to be assumed, of course, that our native forest trees, at least 

 in some regions, would: be susceptible to attack. It may also be 

 assumed that the tropical fungi have built up strong parasitic 

 tendencies in order to counteract continuous growth in their exo- 

 genous and endogenous growing hosts, which would tend to make 

 them more vigorous and destructive when growing under reverse 

 conditions. Of course, all of this is pure conjecture, for our 

 knowledge as to how fungi endemic in tropical and foreign coun- 

 tries would react to the low temperature of a more temperate 

 climate, is very limited. Unless their food requirements are at 

 variance with that which they would find in our native trees, the 

 lower temperature can be expected to stimulate growth. The 

 average temperature for the growth of wood^destroying fungi is 

 comparatively low. Falck'^' has shown that the growth range for 

 a number of wood-destroying fungi lies between 3° and 44° C, 

 with an optimum temperature between 18° and 35° C. Humph- 

 rey^ states that *' for the majority of species the most favorable 

 temperature lies between 75° and 85° F." This author further 

 states that out of a series of some 50 species tested none would 

 grow above 118° P., and in general wood-destroying fungi are 

 much less tolerant of high temperatures than low ones, while 

 temperatures slightly above the freezing point will usually permit 

 some growth. This writer found that on storing a large number 

 of stock cultures of difTerent species in an ice box where the 



has been investigated. The mere fact that they are found growing from 

 wounds does not imply that they would attack the living cell. Fomes pini- 

 cola, one of the most common saprophytes, chiefly on coniferous wood, not 

 infrequently enters through wounds and destroys the heartwood of living 

 trees, but it would not be considered parasitic. Some such term as wound 

 fungus would be more conservative, and would merely imply that, the fungus 

 grew on the dead wood of wounds or entered the heartwood in this manner. 



6 Falck, Richard. Wachstumgesetze, Wachstumfaktoren und Temperatur- 

 werte der holzzerstorenden Mycelien. In Moller, Alfred. Hausschwamm- 

 forschungen. Heft i, p. 53-154. 1907- 



. Die Lenzitesfaule des Coniferenholzes, eine auf kultureller Grund- 



lage bearbeitete Monographie der Coniferenholz bewohnenden Lenzites-Arten. 

 In Moller, Alfred. Hausschwammforschungen. Heft 3, 234 pp. 24 fig., 7 pi. 

 1909. 



7 Humphrey. Timber decay and its growing importance. Railway Age 

 Gazette, p. 10. Dec. 15, 1916. 



