510 RESEARCHES ON FUNGI 



and hold that its life-history is simply a shortened form of a 

 Eu-puccinia such as Puccinia Violae. As possibly bearing on this 

 question, it seemed to me of interest to determine whether or not 

 the discharge of spores from the basidia of Endophyllum takes 

 place in the manner which is normal for the other Uredineae as 

 well as for the Hymenomycetes. 



In June, 1915, Mr. W. B. Grove kindly procured for me from 

 Credenhill Camp, Herefordshire, some shoots of the Wood Spurge 

 {Euphorbia armjgdaloides) which were strongly infected with Endo- 

 phyllum Euphorbiae-sylvaticae. The aecidia were thickly set on the 

 backs of the leaves (Fig. 206, A) ; and, when the shoots were shaken, 

 the ripe aecidiospores fell out of their aecidia in the form of a fine 

 powder. 



The following method was employed in cultivating the aecidio- 

 spores. Some glass slides were smeared with a warm 10-per-cent. 

 gelatine solution. As soon as the gelatine had cooled and set, an 

 infected shoot of the Euphorbia was shaken over each slide. A 

 light shower of aecidiospores thus came to settle on the surface of 

 the gelatine. The slides were then put in Petri dishes, the bottoms 

 of which had been covered with moistened blotting paper. The 

 Petri dishes were kept at a room temperature of about 18° C. The 

 cultures were made at 9 p.m. A considerable number of the 

 aecidiospores germinated during the night, and the discharge of 

 the basidiospores took place in abundance during the succeeding 

 morning and afternoon. 



Observations upon the germinated aecidiospores were carried 

 out as follows. A slide was removed from a Petri dish, set on the 

 stage of the microscope, and a favourable place in the preparation 

 found as quickly as possible with the low-power objective. A glass 

 ring, 22 mm. wide and 2 mm. high, was then rested on the slide so 

 as to include the favourable place, the high power of the microscope 

 was applied, and finally the space between the top of the glass ring 

 and the objective was covered over with strips of wet blotting paper. 

 Thus a small damp-chamber was constructed, and it became pos- 

 sible to look down upon a number of germinated aecidiospores and 

 to observe their basidia whilst these were continuing their normal 

 development. 



