754 THE AMERICAN NATURALIST. [VoL. XXXIII 
the consideration of the infection of uninjured tissue. By means of 
injecting into plants water containing Botrytis spores, it was possible 
to note the effect of their germination far removed from the point of 
injury. He found that from the time when the spores in the inter- 
cellular spaces began to produce any sign of hyphae, the near-by cells 
showed evidence of disorganization. The cell walls turned brown 
and ultimately also the cell contents, until eventually death of the 
affected parts ensued. By numerous experiments he arrived at the 
conclusion that this is due to the secretion of a poison by the germi- 
nating spore. Into the cells so killed the Botrytis mycelium can 
now readily make its way, and by further excretion of the poisonous 
substance spread, mayhap, through the whole tissue of the plant. 
According to the author, it is by this means alone that Botrytis is 
able to assume its apparently true parasitic habit, although the hyphz 
cannot penetrate the living cells themselves. Experiments with 
Penicillium showed that this fungus has no such power of killing 
cells on which it is growing ; in other words, that it does not secrete 
a poisonous substance, and can only penetrate cells which themselves 
are in a weakened or diseased condition. The relation of Botrytis 
to its host is simple compared with that of a true parasite, which 
usually induces complicated hypertrophies. With Botrytis it is 
simply a question of killing the cells to effect an entrance in the first 
place, and a continuance of this process to effect a further develop- 
ment of the fungus. A large class of plant diseases must be in- 
cluded under the same head. Under natural conditions, where 
infection takes place through an injured surface, the spread of the 
fungus resolves itself into the question as to whether the host plant 
can form an impermeable covering of wound cork faster than the 
hemiparasite can destroy the cells around the point of infection. 
Notes. — No. 15 of the new series of Contributions from the Gray 
Herbarium, by M. L. Fernald, deals with certain species of Eleocharis 
and Scirpus, and is published as No. 19 of the current volume of the 
Proceedings of the American Academy of Arts and Sciences. 
A conspectus of the genus Lilium is published by Professor Waugh 
in the Botanical Gazette for April. 
‘Grazing Problems in the Southwest” and “ Poa Fendleriana and 
its Allies” are the titles of two recent papers by J. G. Smith, pub- 
lished from the Division of Agrostology of the United States Depart- 
ment of Agriculture, 
