LAESTADIA. 217 



found light on into autumn, even throughout the winter. 

 Hibernating sclerotia are also produced, the cells of which grow 

 out directly into septate conidiophores with oval conidia. 

 Perithecia, externally resem1)ling pycnidia, are formed in May 

 and June on the fallen berries of the preceding year. The 

 asci have gelatinous walls, which swell and burst so as to 

 ejaculate their spores. Viala and Eavaz successfully infected 

 living grapes by means of the larger conidia, and also by 

 the germinating ascospores. 



The disease is one of the most dreaded in America. It has 

 been found also in Europe, having been observed in France 

 since 1885, though not as yet in Germany, Switzerland, Italy, 

 or Spain. Moist situations are favourable to it. As with 

 other diseases of the vine, the various varieties liave ditl'erent 

 powers of resistance, and a judicious selection of varieties may 

 prove a good preventive measure. According to Yiala, the 

 blaek-rot is founil in the United States on both wild and 

 cultivated vines, but never on the fruit of Vitis rujjcsfri.s, V. 

 Bci'lancici'i, V. cincrca, V. Lii/seroinii, V. Monticola, and V. 

 candicans, and very rarely on their leaves. Tlie "vine-stocks" 

 themselves suffer little or nothing from the disease. IJathay 

 says that Vitis riparia, V. rupestris, and V. Solonis, so im- 

 portant as grafting-stocks, are seldom affected ; the green 

 shoots, of other species, however, may be attacked and the 

 disease be transmitted through the graft-slip. 



For combating the disease, Galloway, Prillieux, and FEcluse 

 recommend Bordeaux mixture.^ 



Laestadia buxi (Uesm.). The perithecia of this species are 

 found as tiny points on yellow spots on tlie lower surface of 

 green leaves of box. This fungus, regarded by Desmazieres as 

 saprophytic, is said by Briosi and Cavara to be parasitic. 



PLEOSPOREAE. 



Physalospora. 



The perithecia are formed under the epidermis, but are 

 otherwise devoid of covering ; they contain asci and paraphyses ; 

 the spores are one-celled, and ovoid or elliptical. 



^For details see Rathay (he. cit.), the American bulletins, etc. 



