204: ASCOMYCETES. 



Dematophora 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 melkus. 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 Dematujjhora. 



According to Yiala," 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 Rosellinm. 



Hartig * suggests impregnation of the vine poles with creosote 

 as a means of combating this disease. 



Strickeria. 



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

 Rohinia Pseudacacia; its parasitism is however not yet fully estaV)lished. 



CUCURBITARIEAE. 



Gibbera. 



The black perithecia, beset with stift" bristles, are developed 

 in large groups on a dark pseudoparenchymatous stroma. 



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

 moist patches of Hijpnvm and other mosses, one often finds 

 the cowljerry {Vaccinium Vitis-Idaca) with its leaves and 



' Beinling, Dax Anftreten v. Rebenkranhheiten in Baden, 1891. 



2Viala, Monor/raphie du Pourridie d. Vignes, 1891. 



^ Berlese, Jxirista di patoh</ia vegeiale, I. 



■^ R. Hartig, Lehrhuch d. Banmkranlhcifcn, English edition, 1894, p. 87. 



