New York Agricultukal Experiment Station. 03 



may strangle a succulent terminal portion; or the fungus may 

 kill the lateral shoots while the main stem remains green. On 

 the older woody stems the spots are considerably sunken, but 

 on succulent shoots this character is scarcely noticeable. The 

 spots are elliptical, their major axes having a length of from 

 three to ten millimeters and lying parallel to the axis of the 

 shoot. At first they are dirty white with a narrow brown border. 

 In a short time several minute pimples, which are at first brown 

 but soon .turn black, appear in the central portion. Microscopic 

 examination shows these pimples to consist of a brown stroma. 

 Neither spores nor setfi? are present at this time. It is in this 

 black-pimple condition that the fungus is generally found. Still, 

 under favorable conditions of moisture the spots fruit profusely; 

 and both spores and seta? may be obtained in abundance at any 

 time by placing spots showing the black pimples in a moi:?t 

 chamber for about 48 hours. However, very old spots may refuse 

 to fruit under any conditions. With the appearance of spores 

 and setae the spots become quite black over the greater part of 

 their surface. The acervuli are numerous and so crowded that 

 it is difiicult to distinguish the individuals even with the aid of a 

 good magnifier. The stroma is dark brown and well developed. 



Several setse are borne on each acervulus. The majority of 

 them are straight but some are bent. They are dark brown and 

 taper uniformly to a moderately sharp point. As a rule they are 

 3-septate, but 2-septate and 4-septate individuals are not uncom- 

 mon. They are 50 to 100;^ in length and unbranched. 



The conida are non-septate, colorless and mostly about 4| 

 times as long as broad, measuring 16-21x4 The majority of 

 them are slightly curved, with both ends rounded or else with a 

 short obtuse point at one side of one end (Plate VI, fig. 3). The 

 young conidia have granular contents and almost invariably a 

 single vacuole near the center; but with age more vacuoles appear 

 and finally they become two to four nucleate. The writer's obser- 

 vations on plants in the greenhouse at Geneva lead him to believe 

 that a high degree of humidity in the atmosphere is necessary 



