14 BULLETIN 418, U. S. DEPARTMENT OF AGRICULTURE. 
VEGETABLE PARASITES. 
The most harmful of the vegetable parasites is a kind of mistletoe 
(Razoumofskya campylopoda) which is, in some localities, very abund- 
ant. This plant attaches itself to the little twigs and causes in them, 
as they develop, swellings and deformities (" witches' broom"), both 
on the main stem and the twigs. It kills single branches outright, 
but seldom causes the death of a tree: it may, however, weaken the 
tree's vitality and impair its value for commercial purposes. A rust 
called Peridermium jilameritosum causes, on the twigs, swellings which 
are quite conspicuous in yellow-pine young growth. Yellow pines, 
especially in the Blue Mountain region, as well as some of their associ- 
ates, are often heavily covered with two lichens— Alectoria fremontii, 
11 black moss," and Evernia vulpina. These plants are not fatal, but 
may injure the host trees by shading their foliage and preventing 
proper bark shedding and aeration. 
Yellow pine is rather free from fungi which cause decay in the 
wood. One of its worst enemies among the fungi is Polyporus schvjei- 
nitzii (butt rot or dry brown rot), which gains entrance through basal 
scars and damages particularly the lower portion of the tree. It is, 
like most forms of decay, a disease which affects old, overmature 
timber, and seems to be particularly abundant on situations where 
the soil is sterile or thin. It is usually difficult to tell from the outside 
appearance of a tree whether it is affected with butt rot. Another 
bad form of decay is Trametes pini (ring-scale fungus, pipe rot, or 
white-pitted rot), which enters the tree at broken tops or in bad 
wounds on the stem and rots out the heartwood. The presence, of 
Trametes pini can usually be detected by the thin, unhealthy bark 
and the " bumpy" stems of seriously affected trees. Fomes laricis 
(chalky quinine fungus, or sap rot) is a third serious fungous enemy of 
yellow pine. It causes a red heart rot with felts of white mycelium. 1 
Its fruiting bodies are generally very large, round, hoof-shaped, with 
a rough white, chalky surface. 
The amount of decay in yellow-pine timber caused by these fungi 
is of course very variable; some thrifty stands are almost free from it, 
and in others it is very bad. On one tract of very overmature timber 
in central Oregon a third of the trees had to be long-butted from 4 
to 6 feet each to get rid of the worthless portion of the first log. The 
scale of over 2,000,000 feet of logs cut in the Blue Mountains shows 
that only 0.9 per cent had to be subtracted from the full scale on 
account of rot. In addition, some worthless trees or portions of 
trees were left in the woods. This would probably indicate for this 
particular tract an amount of defect on account of rot equivalent to 
about 2 per cent of the total stand. 
1 IT. S. Department of Agriculture.-Forest Service Bulletin (unnumbered), "Forest-tree Diseases Com- 
mon in California and Nevada," by E. P. Meinecke. 
