PERIODICAI. LITERATURE 799 



cellulose, is Botrytis vulgaris Fr. The author made a very complete 

 study of this fungus and describes a few of the most important results. 



The infection of plants by Botrytis spores is uncertain in drops of 

 pure water, a condition which afifects probably all wound parasites. 

 Infection is first secured when the parasite secures strength to attack 

 after receiving nourishment from dead organic matter, as is the case in 

 the resultant exudation from wounds. Infection is always secured 

 on wounded areas, and as far as the' interior character of plants is con- 

 cerned, Botrytis is onmivorous. 



The variations in the effect of illness in different plants is due to 

 interior characteristics of the plants. Under these characteristics may 

 be considered the water content, chemical composition, and aeration of 

 the leaves. In a sickly leaf, the infiltration in the intercellular spaces 

 cuts off, in part, the ventilation. If the epidermis happens to be thick 

 with few stomata and covered with waxy surface, the growth of 

 Botrytis is slowed up since it is extraordinarily air-requiring and in 

 such succulent plants as Sedum maximum and others it makes slow 

 progress. In thin, succulent leaves with numerous stomata, infection 

 progresses rapidly; in dry leaves, poor in sap, as Quercus fagus, in- 

 fection progresses slowly. It is not established that certain chemical 

 elements occurring in concentrations within the leaves check the 

 growth of Botrytis. Where this was apparently the case, the cultures 

 showed that the fungus was not afTected by these bodies. Additions of 

 small amounts of amydalin and tannin had no eifect. 



The anatomical investigation of diseased areas proved that chloro- 

 plasts and nucleus very often are intact and that the cell-wall is not 

 always decomposed. The cuticula remains undisturbed. 



Under the influence of the fungus the cellulose of the parenchyma 

 cells is affected as follows : 



DECOMPOSED IN — PARTI.Y DECOMPOSED IN — 



Corylus tubulosa. Asarum europaeum. 



Quercus sessiliflora. Saponaria officinalis. 



Ulmus montana. Prunus padus. 



Urtica dioica. Sorbus torminalis. 



Rumex obtusifolius. Sorbus aria. 



Ranunculus repens. Rhamnus frangula. 



Syringa vulgaris. Ligustrum vulgare. 



Fraxinus excelsior. Viburnum dentatum. 



Glechoma hederacea. Vibrunum lantana. 

 Stachys silvatica. 

 Sambucus nigra. 

 Populus alba. 



