﻿50 BOTANICAL MAGAZINE. [V oi. xx, 



Cceoma on Prunus Pseudo-Cerasus Lindl. (Kuroishino near Morioka, May 

 25, 1904) and P. Gray ana Max. (Kuroishino near Morioka, May 25, 

 1904). The fungus on the former plant was still immature, but its 

 manner of development as well as its influence upon the host are quite 

 the same as Shirans type specimen of C. radiatum. The fungus on the 

 latter plant attacks the young shoot and forms large sori all over the 

 upper surface of the affected leaves. In respect to the dimension of the 

 spore as well as to the form and manner of development of the sorus the 

 fungus seems to be identical with C. Maldnoi. However, the influence 

 which it exerts upon the host is less energetic : hypertrophy of leaves is 

 not so remarkable as on P. Mume, stipules are scarcely deformed, and the 

 growth of the stem affected seems also to be less influenced. It is still 

 unknown whether the present fungus causes witch's broom like O. radiatum 

 or chloranthy like C. Hakinoi. As a whole we find that the fungi on 

 three different kinds of Primus are morphologically closely allied. The 

 answer to the question whether they are three distinct species or rather 

 belong to a single species attacking different hosts, would depend upon the 

 results of comparative studies of their life history. 



Botanical Laboratory, Imperial University, Tokyo. 



EXPLANATION OF FIGURES IN PLATES III AND IV. 



Plate III. 



Fig. 1. Diseased and normal shoot of Prunus Mume. The diseased 



leaves being covered densely by the sori of the fungus are 



rolled back, x \. 

 Fig. 2. Diseased flowers, a, partially affected flower with elongated and 



enlarged ovary, and with less deformed stamens, petals and sepals. 



b, c, incompletely chloranthic flowers. Some anthers remain 



unchanged, d, completely chloranthic flower still inclosing. The 



surface is covered with spermogonia. xf. 

 Fig. 3. Chloranthic flower at full growth with numerous sori of the 



fungus, x f . 

 Fig. 4. Phyllomorphic floral organs, a-d, petals, e, petal and abortive 



stamens, f-i, stamens, j-4, pistils, x f . 



