8 BULLETIN 212, U. S. DEPARTMENT OF AGRICULTURE. 
The writer finds this mistletoe to be the cause of serious damage to 
the jack pine at its most western extension or where it approaches the 
zone of the lodgepole pine in the north. 
SAPROPHYTIC FUNGI. 
Aside from the previously mentioned wood-destroying species, 
which in many cases continue alive after the death of the host, 1 the 
usual strictly saprophytic fungi of coniferous woods are found on cut 
or fire-killed jack pine. Ceratostomella pilifera Ft., the blue-stain 
fungus, appears very rapidly after the death of the tree. In moist 
situations, species of Auricularia and Dacryomyces are surprisingly 
abundant, but can be of little importance, as the mycelium does not 
penetrate the wood to any appreciable distance. The first fungus 
of importance is Polystictus abietinus Dicks. This is a sap-rotting 
species and is seldom absent from fire-killed trees after the second or 
third year. Second in importance is Lenzites sepiaria Ft., which 
works both in the sap and in the heartwood and usually appears on 
the fallen trunks after they have lain for three or four years, following 
up the first-mentioned fungus. The Lenzites appearing on jack pine 
is invariably the true, small, thin-fruited form, with radiating gills. 
Lenzites sepiaria is as easily recognized by the orange-yellow color 
of its growing margin as the young, growing Polystictus abietinus is 
by its beautiful purple tinge. Fomes pinicola Ft. has very little to 
do with the decay of fallen jack pine. This fungus has not been 
found to be very common. Polyporus palustris Berk, and Curt, 
occasionally appears, but is more common on dead Norway pine. 
Fomes carneus "Nees" very rarely occurs on jack pine. Lentinus 
lepideus Ft., Polyporus sulphur eus Ft., and Trametes sepium have 
been collected by the writer on dead jack pine, but they are very 
rare. Resupinate Thelephoraceae occur only in the moist stands of 
mixed species. Those which may be considered of importance in 
the decay of fire-killed timber in the forest are Corticium byssinum 
(Karst.) Burt., C. sulphureum Pers., C. galactinum (Ft.) Burt., 
Coniophora olivaceae (Ft.) Bres., and Peniophora globifera E. and E. 
A yellowish white Poria which goes under the name of P. subacida 
Peck is occasionally found on fallen jack pine in Minnesota. This 
fungus has been observed by the writer in a fruiting condition on old 
boxes and barrel staves made from newly felled living trees. This 
indicates its probable parasitism on jack pine in the living forest. 
i This is a fact that is not generally appreciated, and on it depends the solution of some very important 
pathological problems in the forest. Vigorously growing sporophores of Trametes pini springing from 
original infections in the living tree have been collected from a fallen western larch which had lain on the 
ground for more than 100 years. This was determined by the age of a western red cedar growing astride the 
fallen trunk. Practically all the more serious wound and root fungi of the genera Trametes, Fomes, Poly- 
porus, and Agaricus in moist situations continue alive indefinitely after the death of their hosts. 
