446 
Notes. 
conidiophores produced in the respiratory cavities and other intercellular spaces was 
usually vertical, and towards the surface of the wound. Examples were observed, 
however, of young conidiophores growing horizontally in intercellular spaces between 
the mesophyll-cells, or, in a few cases, vertically, with the apex of the conidiophore 
directed away from the surface of the wound. 
In several cases hyphae had penetrated laterally, in a direction parallel to the 
surface of the leaf, from the edge of the wound, and occurred in the intercellular 
spaces in the middle of the mesophyll, at places where all the tissues, including 
the epidermis above and below, were uninjured. In such places both haustoria and 
young conidiophores were produced. 
Figures are given illustrating the details of the growth of the hyphae in the 
interior of the leaf, and the production of haustoria and intercellular conidiophores. 
The author, reviewing the results of the investigations, points out that they 
afford proof that E. graminis is not, as perhaps might have been expected, so highly 
specialized as an ectoparasite as to be necessarily restricted for its food-supply to 
cells of the epidermis ; but shows itself capable of immediate adaptation to conditions 
closely resembling those obtaining in endophytism. 
This fact suggests the possibility that under some circumstances the mycelial 
hyphae of species of the Erysiphaceae which are normally ectoparasites may penetrate 
into the internal tissues of their host-plants exposed through wounds caused in nature 
by the attacks of animals or by physical agency. It is pointed out, however, that the 
successful entry of the hyphae might be prevented, either by the drying up of the 
superficial layers of cells, or by the healing processes shown by many actively 
growing leaves. 
ERNEST S, SALMON. 
Kew. 
