264 A XKW APPLK TREE CANKER. 



of the families of the Sphseriales, characterised by having 

 stromate perithecia and rather large ascospores. The jncnidial 

 ^tage belongs to the genus Dothiorella. and, in .some oases, when 

 not stromatic, possibly to the genus Macrophoma. 



This fungus has many points in common with B. ribis, des- 

 cribed by Grossenbacher and Duggar (2). The chief dili'erence 

 lies in the greater width of the ascus, which in B. ribis is 17-20/x. 

 Also the stromata are, as a rule, larger in diameter, this ranging 

 from 0.5 mm. to 4 mm., 2 mm. being most usual. 



It has afifinities also with Botryusphcrria pntiii, descriljcd Ijy 

 McAlpine (3), and occurring on dead apricot and plum twigs. 

 This fungus differs, however, in having wider perithecia 

 (300-400/1), and the ascospores being slightly larger (20-24 -^ 

 8-9/i), and having finely granular contents. 



The characters of Dothiorella mali, E. and E. (4) on dead 

 branches of Pints malis seem to agree in some particulars with 

 the Dothiorella stage of the fungus under discussion ; the 

 pycnospores of the latter are slightly longer, the stromata not so 

 large, and the spores not granular. 



As this fungus seems to be a species hitherto undescribed, I 

 propose the name Botryosphcrria uvali, n.s])., for it. 



Cultural Characters. 



Cultures from the pycnospores on most nutrient agar-agar 

 media are at first pure white, the mycelial growth being cott(Miy. 

 The colour gradually darkens from the centre outwards, through 

 grey to greenish black, or almost black. 



This holds for the following media : Prune agar, malt ex- 

 tract (5), oatmeal agar, Wittes' Peptone (6) medium. Coons' 

 nutrient solution (7), and also for vegetable media such as 

 rice tubes, potato cylinders, bean stems, apple twigs and apple 

 chips. The production of the dark colour seems to be more 

 or less inhibited in modified Uschinsky's solution ( S ) , the only 

 evidence of darkening being a slight greyish tint in the aerial 

 mycelium. Growth in beef broth agar is peculiar and charac- 

 teristic. Active growth seems to stop when the colony reaches 

 about two inches in diameter ; the mycelium is sub-felty and 

 white; the submerged nncelium at the periphery forming a 

 band or border about one millimetre wide turns black ( Plates 

 XXV, XXVI) in the case of cultures incubated in the dark, and 

 remains colourless in the case of cultures in light (XXVa.). 

 Chromogenesis as observed by ( Irosscnbacher and Duggar (i;) 

 for Botryosphcrria ribis growing on starch paste was obtained 

 when this fungus was grown on starch paste — 5, and — 10, 

 in the lights the colour being Madder Brown ( 10). 



The production of this colour, however, was a])parent for 

 only a very short while, disappearing as the cultures got older. 



Light has an important action in the darkening of the 

 mycelium; although not always essential for the development (jf 



