Nov. 15, 1925 
Longevity of Teliospores of Gronartium ribicola 
905 
columns 4, 7, etc., of Table IV, and in similar columns of our other 
tables, X indicates that less than one-third of the visible teliospores in 
the column germinated; XX indicates that between one-third and 
two-thirds of the visible teliospores germinated; while XXX indicates 
that more than two-thirds of them germinated. This method of 
estimating the number of germinating teliospores is not satisfactory, 
but no really desirable method of doing this has yet been devised 
{10, 17). . .. 
While the present paper is concerned primarily with the longevity 
of the teliospores, tne writers 7 observations on their manner of 
germination, etc., may well be mentioned here. The following phe¬ 
nomena have been noted more or less frequently in these tests. They 
are not new to the writers, and the references indicate others who have 
made similar observations. They are chosen especially for work with 
Gronartium ribicola , and in default of this, with some other species of 
Cronartium. 
The teliospores germinate normally in situ in the telial column, 
and with the latter still upon the host leaf ( 15, 5, 4 ). The basal spores 
in a telial column are the youngest, and germination proceeds in each 
column from the tip downward as the teliospores mature {20, 15, 5). 
For this reason we may have a telial column at the tip of which are 
teliospores which have germinated, and still have in it other telio¬ 
spores which will readily germinate when the necessary favorable 
conditions are furnished. Each teliospore normally puts forth a 
germ tube. If the tube immediately reaches the air, it soon divides 
into a four-celled promycelium {20, 14 , 15, 5, 4, 17). If the telio¬ 
spore is immersed in water, it may fail to germinate at all, or may 
produce a long, slender tube, which appears to try to reach the air 
{5, 4) • Sometimes this tube forms a four-celled structure at its end, 
the cells of which soon fall apart, forming what are evidently resting 
spores {15, 4 )• If the germ tube from the teliospore should reach 
the air, it immediately forms a four-celled promycelium. Air 
seems to be necessary for the formation of normal promycelia. As 
the germ tube elongates from the teliospore, and especially when the 
promycelium is formed, the protoplasm of the teliospore enters the 
tube and fills its outer end {20, 15, 5, 4 )• The four cells of the pro¬ 
mycelium receive this protoplasmic mass, and when they in turn 
germinate the protoplasm migrates to the ends of their germ tubes. 
If secondary or tertiary sporidia are formed, the protoplasm con¬ 
tinues to migrate to the outermost structure, leaving those behind 
empty. Normally each promycelial cell germinates, forming a germ 
tube. This soon forms a small, round conidium called a sporidium 
{20, 14, 15, 5, 4 ). The sporidium germinates by putting fortn a germ 
tube; this may quite frequently produce a secondary sporidium 
nearly as large as the primary one. Sometimes the process is repeated 
and a tertiary sporidium formed {14, 15, 21,5, 4, 17,). In the experi¬ 
ments described in this paper, secondary sporidia were noted in 
cultures of teliospores from Ribes americanum, R. glandulosum, R . 
nigrum, R . rotundifolium, R. triste, and R. vulgare . They were not 
noted in material from R . cynosbati and R. odoratum. 
In some of their tests the writers noted the effect of massing of the 
telial columns in decreasing the germination of the teliospores, 
which is mentioned by Brown {3) for spores of Botrytis cinerea . 
