Flawerless-Plant Study 



feel the grandeur of tree life can but look with sorrow upon these fungus 

 outgrowths, for they mean that the doom of the tree is sealed. 



There are many species of bracket fungi. Three of these are very 

 common. The gray bracket, gray above and with creamy surface below 

 (Polyporous applanatus) is a favorite for amateur etchers, who with a 

 sharp point make interesting sketches upon this naturally prepared plate; 

 this species often grows tc great size and is frequently very old. Another 

 species (P. lucidus) is in color a beautiful mahogany, or coral-red above 

 and has a peculiar stem from which it depends; the stem and upper sur- 

 face are polished as if burnished and the lower surface is yellowish white. 

 Another species (P. sulphurens) is sulphur yellow above and below; 

 usually many of these, yellow brackets are grouped together, their fan- 

 shaped caps overlapping. Many of the shelf fungi live only on dead wood, 

 and those are an aid in reducing dead branches and stumps until they 

 crumble and become again a part of the soil. However, several of the 

 species attack living trees and do great damage. They can gain access to 

 the living tree only through an injured place in the bark, a break caused 

 perhaps by the wind, by a bruise from a falling tree, or more often from 

 the hack of the careless wood-chopper; often they gain entrance through 

 an unhealed knot-hole. To one who understands trees and loves them, 

 their patient striving to heal these wounds inflicted by forces they cannot 

 withstand is truly pathetic. After the wound is made and before the 

 healing is accomplished, the wind may sift into the wound the almost 

 omnipresent spores of these fungi and the work of destruction begins. 

 From the spores grows the mycelium, the fungus threads which push into 

 the heart of the wood getting nourishment from it as they go. When we 

 see wood thus diseased we say that it is rotting, but rotting merely means 

 the yielding up of the body substance of the tree to these voracious fungus 

 threads. They push in radially and then grow upward and downward, 

 weakening the tree where it most needs strength to withstand the on- 

 slaught of the wind. Later these parasitic threads may reach the cam- 

 bium layer, the living ring of the tree trunk, and kill the tree entirely ; but 

 many a tree has lived long with the fungus attacking its heartwood. A 

 bracket fungus found by Professor Atkinson was eighty years old; how- 

 ever, this may have shortened the life of the tree a century or more. 



After these fungus threads are thoroughly established in the tree, they 

 again seek a wound in the protecting bark where they may push out and 

 build the fruiting organ, which we call the bracket. This may be at the 

 same place where the fatal entry was made, or it may be far from it. The 

 bracket is at first very small and is composed of a layer of honeycomb 

 cells, closed and hard above and opening below cells so small that we can 

 see the cell openings only with a lens. These cells are not hexagonal like 

 the honeycomb, but are tubes packed together. Spores are developed in 

 each tube. Next year another layer of cells grows beneath this first 

 bracket and extends out beyond it ; each year it is thus added to, making 

 it thicker and marking its upper surface with concentric rings around the 

 point of attachment. The creamy surface of the great bracket fungus on 

 which etchings are made, is composed of a layer of these minute spore- 

 bearing tubes. Not all bracket fungi show their age by these annual 

 growths, for some species form new shelves every year, which decay after 

 the spores are ripened and shed. 



