1390 REPORT OF THE DEPARTMENT OF BOTANY OF THE 
fruit and canes. The spores are formed in pustules, technically 
known as acervuli, which originate underneath the epidermis of 
the leaf, chiefly on the upper surface. The epidermis beeomes 
blackened and elevated so as to form a small pimple. At matur- 
ity this pimple is ruptured at the summit and the spores escape 
in a gelatinous mass which appears as a whitish or flesh colored 
speck at the center of the spot. The spores, which are one-celled 
and uncolored, are somewhat variable as to size and shape. 
Usually they are strongly curved and somewhat larger at one 
end. (See Plate I, Fig. 2.) As we have found them, the spores 
measure 12 to 24y in length by 5 to 9» in width, the most com- 
mon size being 19 by 7+. 
In our experience there has never been any difficulty to find 
the spores in abundance on the affected leaves. They are also 
fairly abundant on the new canes and on the petioles. On the 
canes they are much more easily found while the canes are fresh. 
Upon drying, the contrast of color distinguishing the acervuli 
largely disappears. From dried specimens of the canes the 
spores are most easily obtained by scraping the bark after a 
brief immersion in water. On the fruit stems and berries the 
spores are found less frequently. 
So far as known, Glwosporiwm ribis has but the one spore form 
above described. However, it is quite possible that there exists, 
also, an ascigerous form in which the fungus passes the winter. 
Fuckel® has suggested such a relationship with Spheria circinata 
Fekl. [—=Gnomoniella circinata (Fckl.) Sacce.] 
By means of artificial cultures Miss Stoneman’ has shown that 
two other species of Gleosporium, G. cingulatum Atk. and G. 
viperatum KK. & E., have in their life cycle ascigerous forms 
referable to a pyrenomycetous genus for which she proposes 
the name Gnomoniopsis. | 
Excellent figures of Glwosporium ribis are found in Briosi & 
Cavara’s Funghi parassiti delle piante coltivate od utili, Fasc. IX, 
Nr. 222. 
*Fuckel, L. Symbole Mycologies, p. 111. 
‘Stoneman, Bertha. A Comparative Study of the Development of some 
Anthracnoses. Botanical Gazette, 26:101-106. 
