1 1 o British Uredinecs and Ustilao;inecE. 



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collect specimens which are perfectly mature, if possible, 

 upon leaves that are beginning to fade from age, and dry 

 them in the ordinary way between blotting-paper. When 

 the spring comes, the affected leaves must be soaked for 

 twenty-four hours in water, and the spores examined to 

 see if any attempt at germination is observable. If not, 

 the soaked leaves may be wrapped in an old, well-washed 

 piece of calico, and buried for a day or two in the ground ; 

 after which treatment, a few spores must be tried in a drop 

 of water on a glass slide. Should they fail to evince any 

 signs of vitality, the leaves must again be buried for a day 

 or two longer, and re-examined. 



The entrance of the germ-tube into the host-plant can 

 be observed in various ways. The promycelial spores can 

 be applied to the surface of a leaf, and sections made a few 

 hours afterwards. This is, however, an exceedingly delicate 

 process, and requires not only patience, but considerable 

 manipulative skill. A piece of the epidermis may be 

 stripped off and laid flat upon a moistened slide, and the 

 spores placed on it ; if the preparation be kept in a moist 

 atmosphere for a few hours, the germ-tubes can be seen 

 boring through the cells. Another plan is to place a mass 

 of teleutospores, which has first been seen by the micro- 

 scope to be in active germination, on a leaf, and to keep it 

 for a few hours under a bell-glass in a moist atmosphere. 

 The teleutospore mass can be seen by the naked eye, and 

 is a guide to the exact part of the leaf to be examined. 

 By a little deft manoeuvring, pieces of the epidermis at this 

 spot can be ripped off with the point of a penknife, and 

 examined either on their external or internal surfaces. By 

 similar methods, the entrance of the uredospore and aecidio- 

 spore germ-tubes can be observed, only, being larger and 

 containing yellow endochrome, the process is less difficult. 

 With most of the Ustilagineas, all that is necessary is to 



