219 
Continuous Rust PRopAaGATION WiTHOUT SEXUAL 
REPRODUCTION. 
C. A. LupDWwiIc. 
With the demonstration of hetereecism in the rusts, the teliospore came 
to be looked upon as primarily a resting spore, for hetercecism was first 
proved for the black rust of grasses, in which the teliospore is a true rest- 
ing spore. It was therefore believed by implication, indeed often stated, 
that the teliospore is the means of carrying rust fungi over unfavorable 
weather conditions and is especially equipped structurally for that fune- 
tion. The other spore forms and the mycelium, except in the comparatively 
rare cases of a mycelium diffused through and perennial in the tissues of 
the host, were not supposed to be able to survive such adverse conditions. 
Later when modern cytological methods were applied to the rusts, it was 
found, as some leading uredinologists had already suspected in a rather 
vague way, that the essential feature of the teliospore is that it is the 
structure in which is begun the series of nuclear phenomena which close 
the sporophytic stage and precede the gametophytic stage with its resulting 
sexual fusions. With this latter idea goes the rather common belief that 
ho type of life, plant or animal, except perhaps the very lowest, can long 
maintain a high degree of vigor without at least occasional sexual fusions. 
It is this idea that has given rise to the belief held in many places that if 
all the barberry bushes could be destroyed, the black rust of cereals would 
not be able to maintain itself more than a few years. Thus we have super- 
imposed one upon the other in the minds of many men these two ideas: 
(1) that the teliospore is necessary to the continued existence of the rust 
because it is the means of passing the winter or other unfavorable season, 
and (2) that it is necessary to the vigor of the fungus because it is the 
structure in which are initiated those changes which culminate in sexual 
fusions and without which such fusions would not take place. The con- 
tinued prevalence early in the season of the grain rusts at great distances 
from any possible «cia of the species, however, led some investigators to 
doubt the validity of the beliefs just recorded. In consequence, a number 
