
20 
were growing in the Garden. While most of the leaves were 
infected, no extensive defoliation occurred. 
The recently reported disease of the poplars, caused by Dothi- 
chiza populea Sacc. & Bri. was collected in both the Park and the 
Botanic. Garden. Only the smaller branches seemed to be in- 
fected. It is probable that this disease will prove serious as it 
has elsewhere. 
The few red cedars in the Park were severely attacked by the 
rust, Gymnosporangium clavipes Cke. & Pk. Practically all of 
the larger limbs, as well as many of the smaller ones, had one or 
more of the characteristic swellings due to the fungus. In May 
the diseased areas were quite conspicuous on account of the 
brightly colored, swollen, gelatinous masses ‘of teleutospores. 
This was the only species of Gymnosporangim found in the 
Park. 
As noted during the previous season the rhododendrons of the 
Park were infected by a fungous disease. The tips and the mar- 
gins of the leaves turned brown and the leaves fell from the 
bushes prematurely. A large proportion of the plants were in- 
fected and were more or less defoliated. The disease, however, 
was mainly confined to the leaves of the preceding year, the new 
leaves of the current season being free from the trouble. The 
fungus has been identified as Laestadia rhodorae (Ck.) Berl. & 
Vogl. The immature ascocarps were very abundantly developed 
on the diseased leaves, but few asci with mature ascospores were 
obtained. 
The roses in the rose garden of the Park were again infected 
with the common rose leaf spot, caused by Actinonema Rosae 
(Lib.) Fr. Some varieties were severely attacked, resulting in a 
partial loss of the leaves. The rose powdery mildew was also 
present, particularly on the rambler types of roses in the Park 
and Garden. 
Only a few powdery mildews were noted. The lilac mildew, 
Microsphaera alni (Wallr.) Salm., was very common in the late 
summer and early fall. The conidial stage of a powdery mildew 
was observed on some young oak sprouts in the Park. Similar 
diseases were very common on the herbaceous perennials in the 
Garden, various composites as the asters, goldenrods, sunflowers, 
and others, being especially attacked. 


