908 
Journal of Agricultural Research 
Vol. XXXI, N©. 10 
Table III .—Time necessary for germination of teliospores of Cronartium ribicola 
Ribes species 
Collected 
Age 
(days) 
when 
tested 
Hours to 
first ger¬ 
mination 
Hours to 
maxi¬ 
mum ger¬ 
mination 
of col¬ 
umns 
Place 
Date, 
1923 
N igram____ 
Edinburg, N_ Y __ _ 
Sept. 30 
5 
2 
12 
Americanum_ 
Warrensburg, N. Y_ 
Sept. 18 
15 
4 
14 
Odoratum._ 
Darrowsville, N. Y__ 
Sept. 12 
20 
4 
18 
Nigrum_ 
Edinburg, N' Y ., __ 
Sept. 7 
25 
4 
23 
“Do. 
Wadbams, N. Y_ 
Aug. 23 
29 
5 
23 
EFFECT OF ALTERNATE WETTING AND DRYING ON THE TELIOSPORES 
A survey of the literature shows that considerable work has been 
done on the effect of alternate wetting and drying upon the telio¬ 
spores of various genera of the rusts (11). But it is also found that 
practically all of this work has been done with those teliospores which 
require a resting period before germinating. Experiments with 
teliospores which germinate upon maturing, and especially with 
teliospores of any species of Cronartium, seem to be scarce. Since 
the writers’ material was exposed to wetting by dew and especially 
by rain, and to the subsequent drying due to the weather conditions 
of the locality, this question became of some importance. The 
observations made by the writers seem to indicate that teliospores of 
Cronartium ribicola which do not start to germinate perceptibly are 
not noticeably injured by subsequent drying. When a teliospore 
once germinates perceptibly, drying seems to kill it. Unless telio¬ 
spores start to germinate, they survive wetting and drying for an 
indefinite number of times, as the writers’ material was wet many 
times, as shown above under 11 conditions during storage of the mate¬ 
rial.” One collection of telial columns of Ribes nigrum , stored out¬ 
doors, germinated for 70 days while some of the same material kept 
indoors lived only 49 days, showing that the repeated wetting to 
which the former was subjected certainly did not shorten the life of 
the teliospores. 
LONGEVITY OF THE TELIOSPORES 
Teliospores from eight species of Ribes were inclqded in these 
tests as compared with those from five species of Ribes in 1921 (16). 
Tables IV and V give the results of the weekly germination tests 
which were made to determine the longevity of the teliospores. The 
latter also includes the maximum longevity which was attained for 
each species of Ribes in 1921. The amount of germination of telial 
columns did not decrease regularly with increase in age in several 
collections of leaves. This was due partly to the variation in the 
amount of pregermination which had occurred and partly to irregu¬ 
larity in the germination which occurred while the material was kept 
outdoors exposed to the weather. The character of the Ribes leaves 
bearing the telial columns had something to do with the longev¬ 
ity of the teliospores (18). 
