84 DISEASES OF FIELD & GARDEN CROPS. [CH. 



the winter. The resting -spores, which were first de- 

 tected in turnips in 1849 by Mr. C. Edmund Broome, 

 M.A., F.L.S., of Batheaston, Bath, were figured by Dr. 

 Montagne, and named by him (like the similar bodies 

 found in diseased potatoes) Artotrogus. The resting- 

 spores or oospores of Peronospora parasitica, Pers., are 

 often extremely common in rotten turnips and mangel- 

 wurzels, as found in the fields in autumn. These roots 

 are often destroyed by a combined attack of the putre- 

 factive mildew of turnips and the fungus of club -root, 

 described further on in this work. In order to see the 

 resting-spores, portions of the brown decayed substance of 

 the diseased root should be looked over till the oospores 

 are found. The less ripe examples are smooth outside 

 or slightly granular, and the more mature specimens are 

 beautifully echinulate, as illustrated, enlarged 400 dia- 



X-40O- 



FIG. 31. 



Resting-spores or Oospores of Peronospora parasitica, Pers. 

 Enlarged 400 diameters. 



meters, at Fig. 31. Dr. Montagne and Mr. C. E. Broome 

 first observed this fact in 1849, for on the original draw- 

 ing in the possession of the Eev. M. J. Berkeley the 

 smooth form is labelled " sp. jun." and the nodulose form 

 "matur" In colour the resting-spores are yellowish- 

 brown. The examples found by Mr. Broome in 1849 ; 

 those illustrated by Professor de Bary in 1863, Ann. Sc. 

 Nat,, 4 ser., vol. xx. again by him in the Beitrage zur 

 Morphologic und Physiologic der Pilze, 1881, pi. 1, under 

 the name of Artotrogus hydnosporus, Mont, (see also Gar- 

 dener's Chronicle, April 26, 1884, p. 544) ; and the speci- 

 mens shown at Fig. 31, agree in size, character, and colour. 



