229 
wecia. It is so common throughout central and eastern regions early in 
the season, as well as later, that the idea of any seasonal migration from 
its region of possible cia is clearly absurd. It must pass the winter in the 
uredinial stage, and it probably does so as mycelium in the leaves of the 
host. We have here a case of a rust which certainly maintains itself in a 
fair state of vigor for some years without the intervention of cecia and 
probably maintains itself indefinitely. Of course it is possible that it is 
constantly being renewed in vigor in the west by the presence of the «cia, 
and that the fungus thus renewed in vigor is slowly but continuously 
migrating eastward; but such a hypothesis strikes one as being fanciful 
rather than likely to be true. 
Puccinia Sorghi, the corn rust, is another species with a wide distri- 
bution. It is usually not difficult to collect in any field of corn after tassel- 
ing time. The infection is usually not heavy, however. The ecia occur on 
Oxalis, but they occur so seldom that they seem to have little to do with the 
actual propagation of the rust. It is probably carried over from one year 
to the next by urediniospores which survive the winter or by the uredinial 
stage in living plants in southern regions. The latter source of infection 
seems more likely for this rust than for wheat rust because of its later 
appearance and less severity. 
Puccinia Asperifolii, the leaf rust of rye, is a rust which has no known 
recia in this country. Its case in America is therefore comparable with that 
of the bluegrass rust in this region or of P. graminis in Australia. It has to 
maintain itself by the sporophytic stage only. 
Uronyces caryophyllinus on carnation is another rust which has no 
wcia in this country. There is no direct evidence that it can maintain 
itself over winter, for it usually appears in greenhouses; but it must have 
passed through thousands of uredinial generations since it was introduced, 
yet it seems to show no particular loss of vigor. 
Puccinia Chrysanthemi is a Japanese species which has been introduced 
into America and Europe. It attacks cultivated chrysanthemums, chiefly 
in ei enhouses. It has now been known in this country for about a decade 
and a half, and during this time it has never, so far as is known, produced 
a teliospore, although in northern Japan and in the mountains of Japan 
they are common. During this time no great impairment of vigor seems to 
have taken place, although chysanthemum growers are able to keep it in 
check by the use of resistant varieties and by the exercise of care in 
watering. 
15—4966 
