564 KUNKEL: ORANGE RUSTS OF RUBUS 
(3), Liro (9), and Fischer (5). Without a doubt, Puccinia Peck- 
jana is the teleuto-stage of Gymnoconia interstitialis. The plants 
of Rubus canadensis L. that were brought here from New Hamp- 
shire bearing the Caeoma and planted out in flower pots were on 
August 15 found to be well infected with teleutospores of Gymno- 
conia. These results, together with the germination tests, seem 
to show conclusively that the orange rust common on wild black- 
berries in the vicinity of Glen, New Hampshire, is Gymnoconia 
interstitialis. : 
It seems proper to report at this point an infection experiment 
with Caeoma nitens. This experiment was performed in 1913 
and 1914, but has not previously been reported. Sixteen plants 
of Rubus villosus Ait. found growing wild in Van Cortlandt Park 
were transplanted to flower pots and placed in a greenhouse. 
The plants were all quite free from rust infection and no infected 
plants were observed near where they were found growing. They 
were brought into the greenhouse the latter part of June. Ten 
of the plants were well dusted with the spores of Caeoma nitens 
and placed under bell jars for about one week. They were then 
placed in the open greenhouse. The other six plants were left 
uninoculated and were used as checks. No infection was observed 
on any of the plants during the summer and fall of 1913. In the 
spring of 1914, however, the young shoots of three of the plants 
that had been inoculated the preceding summer bore leaves well 
infected with Cacoma nitens. None of the check plants gave any 
infected shoots. The experiment shows that the spores of Caeoma 
nitens are capable of infecting new plants. It further shows that 
the Caeoma can reproduce itself without an intermediate stage. 
A similar experiment was performed in which the teleutospores of 
Gymnoconia interstitialis were used instead of the functional teleu- 
tospores (aecidiospores) of the short-cycled form. Ten plants of 
Rubus procumbens were inoculated by scraping teleutospores from 
mature sori with a wet knife blade and then smearing them over 
the surface of the leaves and young shoots. The plants thus 
inoculated were kept under bell jars for one week and then placed 
in the open greenhouse. They have been under observation for 
more than two years but the plants have not become infected. 
The viability of the spores was shown by germination tests and 
