102 
IOWA ACADEMY OF SCIENCES 
of the type of a new species, P. coloradense. Vhe latter specimen con- 
tains only spermagonia but the Demetrio specimen shows the peculiar 
lacerate peridium due to the breaking off of the “cover” as it were, so 
nicely figured by Albertini and Schweinitz. And by Prof. CrandalP in his 
distribution of Colorado fungi as the accidium of GTirysomyxa rhodo- 
dendri. 
It appears to me that there are good grounds for considering it dis- 
tinct from the European P. aMetinum or the form found in the White 
Mountains of New Hampshire, a point which I shall discuss more in 
another connection. The species under the name of decolorans has been 
distributed by Holway on thePicea mariana from St. Louis Co., No. 93. 
Specimens kindly sent me by Prof. MacMillan agree with the White 
mountain specimens. 
General Characters. This parasite produces bird's nest distortions 
as P. elatinum. The branches and leaves are much lighter in color than 
the normal being usually pale yellow. The distortions vary from a few 
inches to three or four feet in diameter. The fungus may appear on the 
trunks of trees as well as the upper and outer branches. It is perennial 
and produces where the fascicled branches appear a slight swelling of 
the stem, which is somewhat more pronounced when it occurs on the 
older branches. The diseased branches are terete and somewhat drawn 
out but not nearly so much swollen as in P. elatinum. The bark is pale 
straw colored becoming darker with age so that the affected branches 
close to the trunk are j’-ellowish brown. The leaves in falling separate 
from their persistent bases upon which there are no fruiting bodies of 
the fungus. Small punctate browmish spermagonia occur in the grooves 
of the tetragonal leaves. The spermagonia of P. aMetinum are described 
as yellowish. The elongated, orange colored, aecidia are few or scattered 
and occur singly, or in groups of single rows between the keels of the 
leaf. They are roundish, cjdindrical or elongated and are from 1-16 to 1-8 
of an inch in length. The aecidia in the true P. aMetinum are much 
elongated and develop at right angles with the leaf; those of the species 
under consideration grow parallel with tb<^ le?^f ‘aurf^’'^e. The wall® of 
the cup (peridium) are white and when ruptured, somewhat lacerated. 
The spores maturing in early August are orange colored. Leaves are 
never much swollen and except for their yellow appearance, appear almost 
normal. 
Microscopic Characters. The cylindrical, lacerate, white, peridium 
consists of colorless, imbricated, closely connected cells measuring 26-375" 
X 262-1875 . 'ixie orange colored spores are large, spherical, subglobose 
or elliptical with roughened \valls and thick epispore. 
The wood is very light; the lumen of the tracheids is larger while the 
w’alls are thinner than in normal wood; resin canals are large with num- 
erous secreting cells; the walls of the tracheids and medullary ray cells 
are not delignified; the pith cells except in the very youngest material, 
are empty, they are large thin walled and not lignified or but slightly s® 
in old material; the mycelium is abundant in the cortex where it is 
1. Colorado Fung. 2. 
