PM Ne 
1892. ] Fungi of Wild and Cultivated Plants. 117 
by being the means of supply of fungus germs. One other 
instance that illustrates a phase of our subject not before 
touched upon may be given. The plant is a familiar one to 
many and painfully so to not a few. This is the apple rust 
(Restelia) that yellows the foliage of the orchard in July and 
shortens the crop at picking time. This fungus plays a 
double role and seems unable to get along with the apple 
tree alone. In a second and very different form, Gymmno- 
Sporangium, it infests the cedar trees, there forming knots or 
galls that become conspicuous as gelatinous balls during the 
Spring rains. These orange colored balls furnish the spores, 
which falling upon the foliage and fruit of the apple tree, pro- 
duce the fatal rust. Later in the season the spores from the 
apple fungus go back, upon the wings of the wind, to the 
cedar and a new crop of galls is obtained for next spring’s 
campaign against the orchard. In this case it is not wild ap- 
ple trees or those of the same family that harbor the enemy, 
but a tree as widely separated botanically from the apple as 
1s well possible. More than this, the fungus changes its 
form in passing from one to the other so that it was not until 
demonstrated by actual cultures that the relation, long sus- 
Pected, could be fully believed. It is needless to say that 
the very evident method of procedure is to destroy cedar trees 
that are anywhere near the apple orchard. A single large 
gall-bearing cedar tree just outside the orchard fence may do 
“a mischief than any enemy that is lurking within the en- 
osure. 
‘ It has been shown by means of a long series of examples 
Ti the evil influences of wild plants may act at long range. 
pl. 
b 
Nature of a Pp j 
n by the in 
“seen but d 
eats of plants is bad, rank growth of weeds is worse, 
