NOTES AND ABSTRACTS. 



315 



The fungus used in the experiments was the conidial stage of the 

 grass mildew (Erysijjhe Graminis DC), a strict ectoparasite under normal 

 circumstances. Young leaves of oats and barley were cut ofi' from 

 seedling plants, and a minute piece of tissue was cut out with a sharp 

 razor from the upper surface of the leaf. In this operation the upper 

 epidermis was removed, and often a considerable amount of the meso- 

 phyll also, so that in inoculation the conidia were sown on the sub- 

 epidermal or deeper layers of the exposed mesophyll, or even on the 

 internal surface of the lower epidermis. After inoculation, the leaves 

 were placed on damp blotting-paper in a Petri dish. By the sixth to 

 eighth day vigorous infection had nearly always resulted, the surface of 

 the wound bearing patches of clustered conidiophores. 



It was found on examining such wounded leaves that the fungus had 

 invaded the internal tissues to a remarkable extent. Where the mesophyll- 

 cells remaining uninjured were several layers deep, the hyphae had 

 penetrated inwards, winding through the intercellular spaces as far as the 

 internal surface of the lower epidermis. Haustoria were sent into the 

 cells of the superficial layer of the mesophyll by the hyphae creeping on 

 the surface of the wound, and into all the deeper layers of the mesophyll 

 by the hyphae running in the intercellular spaces. The cells of the lower 

 epidermis were also attacked, the internal wall having been penetrated. 

 The sheath- cells of the vascular bundles were much invaded by very 

 vigorous haustoria. The haustoria formed in the cells of the internal 

 tissues resemble in every way those which occur normally in the epidermal 

 cells. 



The hypha? enclosed in intercellular spaces, either just below the 

 surface of the wound or deep down in the internal tissues, struggle to 

 produce conidiophores. The respiratory cavities over the stomata of the 

 lower epidermis were in a great number of cases full of vigorous hypha? 

 producing young conidiophores. The direction of growth of the young 

 conidiophores produced in the respiratory cavities and other intercellular 

 spaces was usually vertical, and towards the surface of the wound. 



The author, reviewing the results of the investigations, points out 

 that they afford proof that E. Grantinis is not, as perhaps might have 

 been expected, so highly specialised 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 hypha? of species of the Erysiphacea 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 hypha? 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. — .4. D. C. 



Etherisation and Chloroformisation of Plants. By J. Foussat 

 (Rev. Hart. Jan. 16, 1905, pp. 45-46). — Further experiments have 

 determined that the effects of these operations are not so transient as 



