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The Museum Gazette 



themselves were attacked. At this time the flowers were 

 falling in natural course, and one of the most conspicuous 

 evidences of disease was that the flower could not detach 

 itself from its footstalk. Instead of dropping off, the invaded 

 flower withers and becomes black, and its foot-stalk withers 

 with it. The downward advance of the fungus is apparently- 

 arrested for a short time at the line of junction. 1 Many 

 specimens show the blackening stopping abruptly at this line. 

 After a short time, however (perhaps only a few hours), it 

 advances beyond it and may spread down to the junction of 

 the footstalk with the stem of the raceme. It may even 

 spread to the whole of the latter. This, however, is unusual, 

 and certainly the rule is for the evidences of the disease, the 

 shrivelling and blackening, to be restricted to parts near to 

 the flower. The mycelium may, however, be advancing root- 

 wards without causing any external changes. The explana- 

 tion of the arrest of the fungus at the " line of junction " is no 

 doubt defective continuity of the fibro-vascular bundles. It 

 is probably much influenced by the age of flower, the 

 resistance being greatest in flowers about to fall. In cases in 

 which the fungus has crossed this line, the flower seldom or 

 never does fall. Its persistence amidst a group of truncated 

 foot-stalks or healthy flowers is a very conspicuous proof of 

 disease, and the condition is a very common one. 



Under the microscope I have repeatedly recognised the 

 fungus flourishing on the petals and the foot-stalk, and some- 

 times even on the anthers themselves. The processes are, 

 however, very rapid, and unless the weather is favourable, it 

 is not very easy to find specimens in an early stage. In one 

 such, in a petal which remained translucent, I was able by 

 transmitted light to recognise the mycelium in the petal sub- 

 stance. Even in cases in which the flower has fallen at the 



1 The term " line of junction " is here used to designate that sort of neck at 

 which the foot-stalk of the flower joins that of the raceme. It is at this line 

 of junction that the flower is detached in the usual course cf things, when the 

 ovules have not been impregnated. 



