DESCRIPTION OF PLATES. 39 
ray cells have been destroyed; m, cross sections of hyphee of Ceratostomella pilifera. 
3. Cross section of a medullary ray, with resin duct showing the internal cell 
walls wholly dissolved out. Masses of brown hyphe, m, of the ‘“‘blue’’ fungus 
extend longitudinally through the ray. 4. Young perithecium of the ‘‘blue”’ fun- 
gus ( Ceratostomella pilifera (Fr.) Winter), grown on pine agar culture. 5. Mature 
perithecia of the “‘ blue’’ fungus ( Ceratostomella pilifera (Fr.) Winter), grown on 
pine agar culture, showing the spores, s, discharging from the top of the beak. 
The line at the side equals 0.1mm. 6. Two perithecia of the ‘‘ blue’’ fungus 
( Ceratostomella pilifera (Fr. ) Winter) just before the discharge of the spores. Peri- 
thecia from culture on pine wood. 7. Twoasci with spores of the ‘‘ blue”’ fungus 
( Ceratostomella pilifera (Fr.) Winter). 8. Spores of the ‘‘ blue’’ fungus ( Ceratosto- 
mella pilifera (Fr.) Winter). 9. Top of beak of perithecium of Ceratostomella 
pilifera (Fr.) Winter, just aiter the discharge of the spore mass. The hyphae 
composing the tip of the beak have spread.out, forming a sort of support for the 
spore mass. 10 and 11. Mediansections of sporophores of the ‘‘ red-rot’’ fungus 
( Polyporus ponderosus, n. sp.), natural size. 
Pirate VIII.—Photomicrographs showing the structure of ‘‘blue’’ wood. Fig. 1. A 
radial section, showing how the hyphe of the ‘‘blue’’ fungus grow in the medul- 
lary rays, being confined almost entirely to the rays. Magnification, 80 diame- 
ters. Fig. 2. A tangential section, showing how the hyphe completely fill the 
medullary rays. Numerous small hyphz grow out into adjoining cells in a 
tangential direction. This makes the wood cells in the photograph look as 
if they were septate. The apparent septa are hyphz. Magnification, 80 
diameters. 
Pirate [X.—A number of pieces of wood from the bull pine (Pinus ponderosa), show- 
ing holes made by wood-boring beetles. The trees from which these pieces were 
taken were in most cases dead, either standing or felled. The “‘ blue’’ fungus 
has started to grow in the wood cells bordering on these holes, and is gradually 
spreading to other cells from these holes asacenter. Note that these wood 
pieces show both radial and tangential surfaces. The piece of wood in the 
center at the bottom of the plate is western hemlock. 
Piate X.—Sections of ‘‘black-top’’ trees of the bull pine ( Pinus ponderosa) , showing 
early stages of the ‘‘red rot’’ caused by Polyporus ponderosus, n. sp. Fig. 1. 
Section of a dead tree 35 feet up from the ground. This tree had probably been 
‘dead for eighteen months to two years. The decay has just started in at several 
points on the north and northwest sides of the tree. Note that the larger part 
of the wood is blue. The healthy, unaffected wood is white. Note also the 
beetle holes in the bark., Fig. 2. A section from a similar ‘‘ black-top”’ tree, 
showing a more advanced stage of decay. The whole section was blue. The 
decay started on the side where the bark prevented the rapid evaporation of 
moisture from the wood and had reached the heartwood. Note the radial and 
tangential sheets of white mycelium. Fig. 3. A section from the same tree from 
which fig. 2 was taken, made some 15 feet higher up. The section is blue, but 
shows few signs of decay. This shows how the ‘‘red rot’’ usually attacks the 
tree somewhere below the crown. 
Piate XI.—Sections of ‘‘ black-top”’ trees of the bull pine, showing advanced stages 
of decay caused by Polyporus ponderosus n. sp. Figs. 1 and 2. These two sections 
were cut from a fallen top of a ‘‘ black top’’ such as is shown in Pl. XIV, fig. 1, 
one near the point where the top broke off, the smaller one near the top of the 
crown. Both show how completely the wood has been destroyed. This stage 
was probably reached about three years after the beetle attack. Fig. 3. The 
lower figure shows a section cut 4 feet from the ground from a standing ‘‘ black- 
top’’ pine. On one side a fruiting body of Polyporus ponderosus is to be seen, 
