NOTES ON RECENT RESEARCH. 



241 



of the author's previous paper (ibid, lxxxviii. 1901) ; see Journal R.H.tt. 

 Vol. XXVI. p. 890^ 



Germination of the Conidia (" Oidium "). — This is favoured by light, 

 and the germ-hyptue are heliotropic and grow faster in the light. The 

 behaviour of the conidia of several species germinating on various plants 

 is followed and described. Conidia of " Erysiphc C ichor acc arum" of the 

 same habit, but found on different species, were again sown on a number 

 of species. Infection failed in most cases of genera, or even species of 

 the same genus, other than the original host. Thus conidia from 

 Artemisia vulgaris failed to infect Senecio, Hieracium, Lactuca, Sonchus, 

 and even Artemisia, Absinthium. The Erysiphe on Senecio vuhjaris 

 failed to infect Hicracium, and only infected Lactuca muralis in one 

 spot of many dusted with the spores. Thus there would seem to be a 

 physiological racial character, to which the morphology gives no clue, 

 just as Ward has shown for Urcdinca. The conidia are but short-lived, 

 and will not survive the winter. Infection from one season to the next 

 can only be effected by the ascospores. It is suggested that these have 

 not the same specialisation as the conidia, but that the host which is 

 directly infested by the ascospore impresses its proper physiological 

 character on the conidia throughout the whole conidial cycle. Thus 

 Erikson showed that the uredospores (Puccinia coronata) developed on 

 the Oat will not affect the Foxtail, and vice versa. But infecting the 

 Buckthorn with the teleutospores from the Foxtail, he obtained the 

 JEcidium, whose spores would now infect the Oat, though this does not 

 hold good for all species of Puccinia. 



SphcerotJieca Hamuli sends haustoria only into the epidermic cells of 

 the Hop, which enlarge enormously. Uncimda Salicis sends merely 

 fine haustoria into the epiderm of the Willow, but large ones are formed 

 by their penetration into the underlying palisade-cells. 



The conidia of Phyllactinia are not abstricted singly, but form true 

 Oidium-chskins. 



Uncimda Aceris produces two forms of conidia : (1) " Normal " large, 

 rounded, easily separating, germinating readily; (2) "starved" minute, 

 oblong, adhering in chains, not germinating. — M. H. 



Figs and Caprification. 



The Fig* : its History, Culture, and Curing. By G. Eisen, Ph. D. 

 {Washington Gov. Pr. Off., 1901. Illustrated by photos and cuts). — 

 This elaborate work consists of 20 chapters. After dealing with the name 

 and derivation, Fig industry and botany of the Fig, the culture in various 

 foreign countries is described as follows : — Smyrna, Greece, N. Africa, 

 Italy, Portugal, France, England, Spain, Southern States of N. America, 

 Mexico, California. 



Chapter IV., consisting of pp. 74-120, deals with caprification, of which 

 an abridged account is appended. 



The concluding chapters are concerned with the technical details of 

 cultivation, as climatic conditions, propagation, planting a Fig orchard, 

 pruning, irrigation, diseases, and insect enemies. Then follow the drying 

 and curing of Figs, as well as packing and shipping fresh Figs. 



R 



