The Hendersonia Disease of Eucalyptus 



Globulus 



A. R. DAVIS 



POMONA COLLEGE, CLAREMONT, CALIFORNIA 



As far as the writer has been able to ascertain there have been no species 

 of the genus Hendersonia as yet described on California eucalypts. Prof. Smith, 

 pathologist of the State Experiment station at Whittier, makes mention as far 

 back as 1909 of a Hendersonia on Eucalyptus globulus, but beyond a few words 

 as to its minor importance as a parasite, docs not describe it. The fungus herein 

 worked out is probably the same as that observed by Prof. Smith and others, 

 altliough we cannot of course be certain. There are a number of fungi on this 

 particular species of eucalyptus and many of them are as yet undescribed; some 

 are parasitic, most of them fortunately saprophytic in their mode of life. With 



Figure 107. Leaf of Eucalyptus globulus affected with Hendersonia. 



the Hendersonia, however, there is hardly a doubt as to its parasitic tendencies; 

 a detailed cultural study was made of it, its method of germination,, growth of 

 hyphae, re-inoculation of healthy leaves, etc. 



The fungus is distributed over quite an area in Southern California, the full 

 extent of which cannot be fully known until further observations are reported. 

 Of a number of trees in and around Claremont the writer has found but few that 

 were not affected to a greater or less extent. The damage actually done by the 

 fungus seems at present to be slight. It confines its attack exclusively to the 

 young, broad leaves, breaking down the leaf tissue and thus preventing a flow of 

 sap. Deprived of its food, the leaf soon dies and falls off. This latter is only 

 true in extreme cases of infection. After the tree has passed the broad leaf 



