IOWA ACADEMY OF SCIENCES 
93 
and Earle, although they have not seen the type specimens of Peck’s P. 
pyriforme, believe it should be referred to P. cereJjrum. The malforma- 
tions on Pinus murrayana in the west are similarb In some cases there 
is but little swelling of the stem, but in others the enlargement of the 
stem or branch is very great. 
The writer- found it abundant on Pinus murrayana in the Big Horn 
mountains of Wyoming in 1897 and in the Uintah mountains in 1900. 
Dr. Von SchrenlU reports it abundant on Bull and Lodge Pole pine. 
General Characters. This fungus produces excrescences on the 
branches of young pines varying from half an inch to two inches in 
diameter. The disease may be confined to a small area or it may extend 
for five or six inches along the branch or young tree. Underwood and 
Earle state that in Alabama the galls may form a large ball, a foot or 
more in diameter. Enlargements of this kind on trunks of both Pinus 
murrayana and P. scopulorum have been observed in the Uintah moun- 
tains and in the Big Horn. These may have been caused by this fun- 
gus but a careful search failed to reveal its spores. On the small younger 
branches the aecidia break through the bark exposing the cdlorless 
thin lining of the cup of the peridium which is large, erumpent, and 
irregularly confluent. These characters are nicely shown as it occurs on 
Pinus rigicla\ The bright colored spores are conspicuous when mature 
and are so numerous as to give the ground and grass surrounding the 
infected plant an orange color. The bark towards the edges is curved 
back fcrmang a rim or border. The saucer-shaped aecidia with , the 
irregular convolutions are very conspicuous. In older specimens the 
wood is uniformly brcwn and resinous. The longer the living tree 
stands the xarger the excrescence becomes. In several instances these 
excrescences had been the result of twenty years growth. Hartig^ 
mentions a case in which P. pini-corticoJa had infected a tree seventy 
years previously. 
Microscopic Characters. The spores are orange colored but soon 
fade. They vary in form from spherical to ovate or pyriform, and are 
prominently roughened. The following measurements were obtained, 
length 3 to 187 mic., width 15 — 22 mic., the spherical ones having a diam- 
eter of 183 mic. The spores are borne in somewhat irregular chains comb- 
ing from short thick basal basidia, under these basidia occur numerous 
short roundish cells that connect with the mycelium that vegetates 
between the cells of the bark but which occasionally may be found alsu 
in the cells. The peridial cells are colorless, long and narrow, somewhat 
pointed at the ends, imbricate and firmly attached together. 15 — 20 x 
40 — 60 mic. The chlorophyll of the host is partially disintegrated. From 
the cortex the mycelium spreads to the wood by way of the cells of 
L Bull. Torrey Bot. Club. 23 : 403. 
2. H. II. Ilurup. Fun{ri CoUeoted in Colorado. Wyoming and Nebraska. Proc. 
Dav. Acad. Sci. 7: 2.>3. ror^tr. Bot. Dept. I. S. C. A. & M. A. 15 
3. Forestry & Irrigation. 7 : CO. f. 2. 
4. Ellis. N. Am. Fung. 1022. 
5. Textbook on the Diseases, Ete! 173. f. 103. Lehrbuch der Baumkrank. 
C4. f. 16. 
