DIE-BACK OF APPLE TREES. 



000 



The cells of the mycelium measure 13.6 — 33.O/A X 5-45 

 — 6.6fj., and are often somewhat swollen (Fig. 3), thus having 

 the general appearance of resting cells. Connections between 

 individual hypha? (Fig. 3) iiave also been observed. 



The pycnidia, which are abundant, are usually scattered. 



Pear Agar slants (PI. 24, b). — After five days, at both 25° C. 

 and 30° C, there was a vigorous, distinctly-raised growth of a 

 violet lilac colour. This growth within 11 days became velvety, 

 and was more of a mouse-grey ; in places were the raised, hum- 

 mock-like bodies containing the pycnidia. Where the fungus 

 extends over the glass, the colour is madder-brown, and where 

 glass, fungus, and medium meet, it is again of a dark neutral 

 tint. 



Fig. 4. 



The m\celium is most frequently 4.4^1^ across, and the 

 individual cells from 14. 85 — 39-6/* long. 



BcerK'ort Agar slants (PI. 24, c, and Fig. 4). — Within five 

 days, at both 45° C. and 30° C, a vigorous greyish, flat mycelial 

 growth appeared, which within 11 days had become more dense, 

 and varied from light to ashy grey. The colour of the mycelium 

 along the glass, and where the fungus, medium and glass meet, 

 was as in previous cases. After 23 days the ashy growth had 

 become dotted over in places by a lighter grey, which in regions 

 looked as though they might lead to the formation of the hum- 



