232 STUDIES OF AMERICAN FUNGI. 



operate in conformity with certain laws which result in great 

 variation in form and habit of the numerous kinds on the ground, on 

 leaves, on branches, on tree trunks, etc. 



Another very favorable indication accompanying the increasing 

 interest in the study of these plants, is the recognition of their im- 

 portance as objects for nature study. There are many useful as 

 well as interesting lessons taught by mushrooms to those who stop 

 to read their stories. The long growth period of the spawn in the 

 ground, or in the tree trunk, where it may sometimes be imprisoned 

 for years, sometimes a century, or more, before the mushroom 

 appears, is calculated to dispel the popular notion that the mushroom 

 " grows in a night." Then from the button stage to the ripe fruit, 

 several days, a week, a month, or a year may be needed, according 

 to the kind, while some fruiting forms are known to live from several 

 to eighty or more years. The adjustment of the fruit cap to a posi- 

 tion most suitable for the scattering of the spores, the different ways 

 in which the fruit cap opens and expands, the different forms of the 

 fruit surface, their colors and other peculiarities, suggest topics for 

 instructive study and observation. The inclination, just now be- 

 coming apparent, to extend nature study topics to include mushrooms 

 is an evidence of a broader and more sympathetic attitude toward 

 nature. 



A little extension of one's observation on the habits of these 

 plants in the woods will reveal the fact that certain ones are serious 

 enemies of timber trees and timber. It is quite easy in many cases 

 for one possessing no technical knowledge of the subject to read the 

 story of these " wood destroying " fungi in the living tree. Branches 

 broken by snow, by wind, or by falling timber provide entrance 

 areas where the spores, lodging on the heart wood of broken timber, 

 or on a bruise on the side of the trunk which has broken through the 

 living part of the tree lying just beneath the bark, provide a point 

 for entrance. The living substance {protoplasm') in the spawn 

 exudes a "juice " {enzyme') which dissolves an opening in the wood 

 cells and permits the spawn to enter the heart of the tree, where 

 decay rapidly proceeds as a result. But very few of these plants 

 can enter the tree when the living part underneath the bark is 

 unbroken. 



These observations suggest useful topics for thought. They 

 suggest practical methods of prevention, careful forestry treatment 

 and careful lumbering to protect the young growth when timber trees 

 are felled. They suggest careful pruning of fruit and shade trees, 



