Fungi 421 



Pine blister rust. Recently the blister rust of the white pine 

 has been brought to America, and it threatens to destroy what 

 remains of our white-pine forests. The alternate host plants of 

 this fungus are the wild and cultivated gooseberries and currants. 

 Attempts are being made to prevent its spread westward, both 

 by cutting the diseased white pine and by systematic destruction 

 of the wild and cultivated currants and gooseberry bushes in 

 newly infected regions. 



Another common rust is frequently seen on raspberry and black- 

 berry bushes along roadsides; it colors the under sides of the 

 leaves with its bright, orange-red spores. In this instance no 

 alternate host is known. 



Mushrooms and toadstools. The largest and most complex 

 of the fungi are the mushrooms and toadstools. They are com- 

 mon in fields and woods and for the most part live on decaying 

 wood and organic matter in the soil. There is no real distinction 

 between mushrooms and toadstools. Some of them are edible, 

 others are indigestible, and some are deadly poisonous. Edible 

 forms are cultivated on a large scale in caves and abandoned 

 mines, and on a smaller scale in cellars. Wild forms should not 

 be eaten unless they are gathered by persons competent to distin- 

 guish the different species, many of which are similar in appear- 

 ance but very different in their effects when eaten. 



The mushrooms as they are gathered are only the fruiting 

 bodies of the fungi. The vegetative part of the plant consists 

 of bundles of hyphae extending in all directions throughout a 

 large mass of soil on which the fruiting bodies appear. It may 

 take several years for the underground vegetative part of the 

 fungus to develop, while the fruiting bodies may develop in a 

 few days. It is the enlargement of the fruiting bodies that per- 

 sons have in mind when they speak of " mushroom growth." 

 This expression leaves out of account the months or years of 

 growth during which the materials were accumulated that led 

 to the sudden production of the fruiting body. 



