204 ASCOMYCETES. 



DeTnatophora forms fine rhizoctonia-strands which grow 

 through the soil from root to root. The mycelium kills the 

 fibrous rootlets, and spreads from these into older roots to 

 form rhizomorph-strands, which, however, have a structure 

 quite distinct from those of Agaricus melleus. The rhizomorph- 

 strands may pass out of the root into the soil, there to form 

 a filamentous mycelium, or, remaining in the root-cortex, may 

 produce rows of black tuberous sclerotia which on maturity 

 break out to the exterior. On the sclerotia, or other parts 

 of the mycelium, bristle-like conidiophores may be developed 

 as branched panicles from which ovoid colourless conidia are 

 abjointed. 



This enemy of the vine is rapidly assuming great import- 

 ance. Thus, for instance, in Baden,^ there is no Phylloxera, 

 but whole tracts of vine land are infested with Demafophora. 



According to Viala,^ Dematophora forms perithecia, which, 

 however, only develop after artificial culture for several years 

 on decayed plants. If this be so, the fungus should be classi- 

 fied between the Tuberaceae and the Elaphomycetes. Berlese,* 

 however, contests this view, and regards it as nearly related 

 to Hosellinia. 



Hartig * suggests impregnation of the vine poles with creosote 

 as a means of combating this disease. 



Strickeria. 



Strickeria Kochii Korb. develops its perithecia on the cortex of living 

 Rohinia Pseudacada ; its parasitism is however not yet fully established. 



CUCURBITARIEAE. 



Gibbera. 



The black perithecia, beset with stiff bristles, are developed 

 in large groups on a dark pseudoparenchymatous stroma. 



Gibbera vaccinii Sow. (Britain). In damp situations amongst 

 moist patches of Hypnum and other mosses, one often finds 

 the cowberry {Vaeeinium Vitis-Idaea) with its leaves and 



'Beinling, Dan Auftreten v. Rebenkranlcheiten in Baden, 1891. 



"Viala, Monographie du Pourridi4 d. Vignes, 1891. 



' Berlese, Sivista di patologia vegetale, i. 



■•R. Hartig, Lehrbuch d. Baxtrnkranhheiten, English edition, 1894, p. 87. 



