244 



THE FUNGI WHICH CAUSE PLANT DISEASE 



M. fragarise (Tul.) Lin.''^ 



Perithecia on leaves, are produced late in the season, globose, 

 subepidermal, membranous, black, thin-walled; asci few, clavate, 



Fig. 179. — Mycosphaerella fragariEe. ft, conidiophores buret- 

 ing through the epidermis; c, arising from apex of a 

 pycnidium; d, summer spores, one germinating; e, s^tion 

 of a spermogonium ; /, section of perithecium; g, ascus 

 containing eight two-celled spores. Aft^er Longyear. 



8-spored, 4Q ii long; spores hyaline, 2-celled, with acute tips, 

 15 X 3^ fi. 



Conidia (=Ramularia tulasnei) abundant in early svunmer on 

 reddish spots, stromatic, conidiophores simple; conidia elliptic 

 20-40 X 3-5 M, 2 to 3-celled. On Fragaria. 



The life history was first studied in 1863 by the Tulasne brothers 

 under the name Stigmatea. The generic name was changed to 

 Sphaerella in 1882 and later to Mycosphaerella. 



