New York Agricultural Experiment Station. 259 



immediately beneath the epidermis and distorted parenchyma cells are 

 frequently included in it. With the enlargement of the pycnidium 

 the underlying cortical tissue is compressed somewhat, giving in- 

 creased area within the collapsing berry and the epidermis and 

 cuticle are lifted so that the pycnidium breaks through and de- 

 velops on the outside to approximately the same extent that it 

 does inside. Fig. 11 (Plate IX). The pycnidia on the woody parts 

 are to be found in greatest abundance in early spring. After the 

 June rains only the base of the pycnidium remains and later the 

 cavity in the tissue occupied by 'the pycnidium is the only visible 

 evidence of this stage. 



Canes which are severely infected the previous season often develop 

 great quantities of the pycnidia, while occasionally pycnidia are 

 developed on the current season's growth. In a vineyard where 

 lightning had run the length of the wires of the trellis a great many 

 shoots were damaged and many, of the internodes rendered pithless. 5 

 On such shoots pycnidia of the fungus were found abundantly. 

 Some of these shoots showed the typical black lesions of the disease 

 as did shoots on neighboring vines in other rows, but the pycnidia 

 were developed abundantly and without regard to the occurrence 

 of lesions. The writer would be inclined to interpret the condition 

 illustrated by Selby and Van Hook (1907) in the same way. 



On July 12, 1909, a green shoot was found bearing mature pycnidia. 

 This is the only instance of such a condition ever noted, except, of 

 course, that the pycnidia develop abundantly on the green or ripen- 

 ing fruit. 



The pycnidium (Fig. 10 — Plate IX), which is dull black externally, 

 is occasionally a simple flask-shaped body. Usually, however, the 

 inner walls are convoluted and sometimes so much so that there is 

 an appearance of several pycnidia united in a common stroma of 

 fungous tissue (Fig. 12 — Plate IX). The walls of these chambers are 

 densely lined with a basidial layer of conidiophores from the ends 

 of which the spores are abstricted. Interspersed among the co- 

 nidiophores there are usually other conidiophore-like bodies bearing 



3 Sometime prior to 1905, Professor Whetzel received specimens of a diseased vine 

 from a vineyardist near Hammondsport, N. Y. An organism was isolated and 

 carried in culture for a long time under the label " pithless cane fungus." 

 Unfortunately the culture finally died out and was discarded. There seems to 

 be no specimen preserved, but from having made numerous test tube transfers 

 of the organism, the writer is of the opinion that this was the dead-arm fungus. 



