270 
Notes . 
The answer to this question is one of great importance to the 
inhabitants of Bermuda, for about four-fifths of their whole exports 
consist of onions. Professor Farlow is of opinion that ‘ the possibility 
that Macrosporium can grow in the tissues of living plants free from 
Peronospora seems to have been demonstrated.’ Mr. Kingo Miyabe’s 
experiments on this point do not, however, seem to me entirely con- 
clusive. He says, ‘ A great number of young plants were started both 
from seeds and bulbs. The spores were sown on different parts of 
the leaves ; and the pots were kept moist under bell-jars, with the 
exception of a few which were left uncovered. The greater part 
of the seedlings were greatly injured by nematoid worms, but those 
which survived did not show any sign of the attack. Out of the twelve 
bulbs, the culture on only two was successful. The spores, however, 
grew in both cases on the sheath of the leaves, and not on the active 
green portions/ Of these two specimens, one failed to produce peri- 
thecia, and in the other the perithecia were arrested when some of 
them were large enough to form paraphyses. In the experiments, 
although everything was in favour of the fungus establishing itself in 
the onion — even the attacks of the Nematodes would weaken the 
plant and render it a more easy victim — only two out of a great 
number of seedlings and plants grown from bulbs were infected, and 
these on the comparatively inert leaf-sheath. Again, the fungi which 
did establish themselves on these two plants either failed to produce 
perithecia, or else produced arrested ones. In this connection it should 
be remembered that a plant may be living whilst part of its tissue is 
dead, and is consequently a suitable nidus for saprophytes. If, how- 
ever, we allow that these two instances afford sufficient ground for 
stating that Macrosporium can, under the most favourable conditions, 
grow on the tissues of living plants in a laboratory, it does not prove 
that, in a state of nature, it can produce a disease. 
I have examined many hundred diseased onions in all stages of the 
attack, but I never saw one suffering from the black mildew ( Macro - 
sporium) which had not previously been attacked by the white (Perono- 
spora) ; and I see no reason to believe that Macrosporium parasiticum 
is capable of causing a disease amongst onions. 
I have unfortunately not been able to find in our libraries here the 
agricultural journals containing the papers quoted by Mr. Kingo 
Miyabe in reference to the parasitism of Pleospora herbarum which he 
has shown to be the ascosporous stage of Macrosporium parasiticum. 
I have, however, been able to refer to Professor Berlese’s article on 
