177 



is a circular opening in the wall called the ostiohmi, and from the 

 bottom arise a series of club-shaped, thin-walled sacs called asci. 

 The asci contain eight spores, each of which is oblong and two- 

 celled. These ascospores are capable of a much longer life than 

 the conidia. 



Fig. 7. — Section of a peritheciuiii, with asci (a), and spores (b) ; 

 an enlarged ascus -with spores on tl;e left. 



Various opinions have been held concerning the real connection 

 of the conidia and perithecia above described. In 1863, the Tu- 

 lasne brothers published elaborate figures* of both, as well as an- 

 other, called the st)dosporic stage, asserting them to be forms of a 

 single species, which they c.alled Sfigmatea (now Sphaerella) Fra- 

 garics. Saccardo, however, in 1879, separated the summer stage 

 from the perithecia], describing the former as Ramularia Tzclasnei.'j 

 Recently Scribner| has asserted his belief, based on direct observa- 

 tion, in the correctness of Tulasne's view ; but none of the au- 

 thorities who have written on this subject, have shown us that 

 the}- were able to propagate one form from the spores of the other, 

 in artificial cultures, and thus actuall}' demonstrate a genetic re- 

 lationship. To accomplish this demonstration was one of the 

 objects of the present investigation. 



THE CULTURES AND ARTIFICIAL INFECTIONS. 



Artificial cultures of the conidia were repeatedlj' made during 

 the autunui and winter. The spores germinated more readily in 



* Selecta Fungonim Carpologia, II., p. 286, pi. 31. 

 t See Sylloge Fiuigonitn, I, p. 50S ; and Michelia, I, p. 536. 

 X Sie Report of the Chief of the Section of Veg. Pathology, (1887), Wu. 

 P- 334- 



