BOY SCOUTS TO COMBAT SHELF FUNGI 281 



injured place in the bark, a broken branch torn off by the wind, and 

 too often from the hack of an axe in the hand of ignorance and 

 carelessness. After the wound is made the spores settle within it 

 and from them grows the mycelium, the fungus threads which push 

 their way into the heart wood, getting nourishment as they grow, 

 and their path is marked by "rotten wood" for rotting simply 

 means the yielding of the substance of the healthy wood to these 

 voracious threads which first push in and then push up and down- 

 ward, weakening the tree and sometimes even girdling it by killing 

 the cambium layer. After these fungus threads have flourished 

 for a time and greatly damaged the tree, they seek another wound 

 in the protecting bark or even push out through the door which they 

 entered and begin to form their fruiting organ which we call the 

 Shelf or Bracket Fungus. One of these is composed of a hard 

 upper surface to which is attached a layer of very small honeycomb- 

 like, tubular cells; in each tube cell spores are developed. When 

 ripe the lower end of the tube opens, letting the pernicious spore 

 dust out to be carried by the wind, until some of it finds another 

 opening into a living tree. 



Now for the Boy Scouts' work. It should be a part of their train- 

 ing to look for these accidental wounds in valuable shade trees, and 

 when found, if the wind has broken a branch and splintered it, to 

 saw or cut the splinters off leaving a smooth stump, and paint it 

 over ; ordinary paint will do if renewed each year or two, but a coat 

 of tar is better. If a boy scout sees a shelf-fungus growing on a 

 living tree he should cut it out and paint a coat of tar over the 

 wound. This may not save this particular tree from the damage of 

 this special attack, but it will save other trees because each year a 

 shelf-fungus grows larger and has more surface for the tubes that 

 bear the spores, and thus becomes a growing menace to all the trees 

 in the neighborhood. 



Professor H. H. Whetzel intended to write an article for this 

 Review, outlining specifically the work of boy scouts in combating 

 one of the most vicious of these fungi species, but his extra duties 

 entailed by the war prevented him from giving us this valuable 

 information, but it will be given in some later number. 



