64 BI7LLETIX 957, u. S. DEPARTMENT OF AGRICULTURE. 
mycelium. Each cell regularly puts forth a stout sterigma on which 
the very thin walled, globular sporidium soon develops. The 
sporidium has a tiny papillalike swelling where it was attached to the 
sterigma. The sporidia are 8 to 10 microns in diameter (20). The 
germ tubes of the teliospores, if developed under water, may not 
form promycelia but extend elongated hyphie (20). Under favorable 
conditions a high percentage of the teliospores may germinate, but 
because of their aggregation into columella? it is impossible to make 
an exact count of the germinating spores. Cooling on ice stimulates 
viability markedly. 
LONGEVITY OF THE TELIOSPORES. 
The longevity of the teliospores of Cronartium ribicola does not 
seem to have received as much attention as that of the peciospores 
and inecliniospores. Gravatt and Taylor made tests with telio- 
spores in 1917 si mil ar to those described as made by them with 
a?ciospores and urediniospores. (See Table II.) Weekly tests 
showed that germination persisted in lot B 35 days, while it lasted 
56 days in lot A. Saprophytic fungi attacked the lot kept on the 
window sill, so that the test probably does not show the longevity 
of healthy teliospores. 
York u in 1918 found that teliospores were still capable of germi- 
nation in tap water after being kept on the plucked leaves 65 days 
out of doors in the shade. A similar test of teliospores kept in the 
dark in the laboratory gave germination for 90 days. 
THE SPORIDIA. 
SEASON OF PRODUCTION OF THE SPORIDIA. 
The sporidia may be produced as soon as the telium is mature, if 
there is sufficient moisture in the air for a number of hours. 
The telia may remain alive on dry dead leaves out of doors for 
more than 65 days, so that sporidia might be produced well into the 
winter in mild seasons, thus prolonging the danger season for pines. 
DISTANCE OF DISSEMINATION OF THE SPORIDIA. 
In work with spore traps by Pennington 46 and Snell in 1918, 
sporidia were caught up to 60 feet from very heavily infected Kibes 
bushes. This was in the eastern Adirondacks, about 8 miles from 
Lake Champlain. Hundreds of pines were examined for infections. 
In no case was infection found on pines as far as 200 feet from Ribes 
plants. Pennington made a study of nine outbreaks in pines in the 
Adirondacks. The infection on pines was confined to an area 
within 100 to 200 feet of the Ribes plants which infected the pines. 
« York. H. H. Op. cit. 
« Pennington, L. H. On. cit. 
