332 
JAMES R. WEIR AND ERNEST E. HUBERT 
measuring 3-7 jj, long. The spore markings of these two are very 
similar and are very pronounced when compared to the other five 
species of the genus. Judging from this it seems that no great reliance 
in respect to identity of species can be placed upon spore measure- 
ments alone. 
It is suggested, in view of the above comparison, although cultures 
are necessary for final determination, that U. copelandi be considered 
identical with U. pteridis and placed under the latter species. A 
technical description of the aecial stage of U. pteridis follows: 
0. Pycnia not found. 
1. Aecia from a limited mycelium appearing on second year 
needles, hypophyllous, not crowded, forming rows on either side of the 
midrib, cylindrical, 0.2 to 0.4 mm. across and 1.5 to 2.6 mm. high; 
peridium colorless, rather delicate, rupturing at apex with fringed 
margins; cells overlapping, majority rhomboid, (10) 15.0-26.6 by 
32.0-43.7 inner walls coarsely and closely verucose, not striate, 
8.3 to 10. o IX thick including tubercles, slightly thicker at one end of 
cell, outer wall, 6.5 to 7.5 ix thick, smooth; aeciospores mostly globoid, 
occasionally broadly ellipsoid (50) 13.3-20 by 1 8.3-24.1 //, standard 
(19 by 22 /x), wall colorless, 2 to 2.5 thick, coarsely and closely veru- 
cose, contents colorless. 
On living needles of Abies grandis and A. lasiocarpa from early 
spring to late fall depending upon elevation. 
The Overwintering of Rusts 
It has long been a puzzle as to why the Pucciniastrum occurring 
on species of Epilobium other than E. angustifolium (L.) Scop, has 
not been found to have its alternate stage upon species of Abies. 
Successful inoculations of Abies sp. with teliosporic material of P. 
pustulatum on E, angustifolium have been made in Europe and in 
America. Fraser^^ secured results in 1912 upon Abies balsamea and 
has collected the aecia in the field. Check results have been secured 
by the writers^^ in 1916. All experiments were properly controlled. 
The uredinial stage of a Pucciniastrum has often been collected 
in the northwestern states upon E. adenocaulon Haus. but never the 
telial stage. Examination of available exsiccati material fails to 
Fraser, W. P. Cultures of Heteroecious Rusts. Mycologia 4: 175. 1912. 
Weir, J. R., and Hubert, E. E. A Successful Inoculation of Ahies lasiocarpa 
with Pucciniastrum pustulatum. Phytopathology 6: 373. 19 16. 
