SUMMER MEETING AT OREGON. 159 



but later become dark brown or black. These bodies are foun i just be- 

 neath the cuticle and as they continue to enlarge they rupture the latter 

 and appear in the form of black postules already described Microscopic 

 examination reveals the fact that the postules are really little sacs or 

 conceptacles, and further investigation shows that they are filled with 

 oval or oblong colorless bodies which are borne upon very slender trans- 

 parent stalks ; the latter arising from the enveloping walls of the con- 

 ceptaclc. A figure is represented by a highly magnified, vertical section 

 of one of the conceptables above described. The oval bodies seen es- 

 caping are the spores (called stylospores) which serve to propagate 

 the fungus rapidly during the growing season. At b is shown the walls 

 of the sac (pycnidium) while below are shown several of the filaments 

 which compose the mycelium. 



Of the actual size of the parts figured, some idea may be ob- 

 tained when we find the entire conceptacle rarely exceeds one two hun- 

 dredth of an inch in diameter. In addition to the conceptacles de- 

 scribed there are others formed in a similar manner which contain 

 bodies more slender and more minute than the spores referred to, these 

 are known as spermagonia, while their contents are termed spermatia. 

 What may be the office of the spermatia has never satisfactorily made 

 out. 



The stylospores are produced in immense numbers, and under favor- 

 able conditions of moisture and heat they germinate readily by sending 

 out slender tubes which easily penetrate the cuticle of the leaves 

 or fruit, and once within the tissues they develop into the mycelium which 

 produces the effects already described. During the growing season, the 

 air in the vicinity of vinyards where the. disease prevails, or has prevailed, 

 is filled with the spores or germs of the disease, only waiting to be brought 

 into contact with some part of the vine to begin their work of destruction. 

 Millions of these spores live over winter in the old berries and other parts 

 of the plant, and just as soon as the young leaves appear, they are sub- 

 jected to the attack of these minute bodies. The fungus passes the win- 

 ter in the old berries in another form, which is really the mature stage 

 of the parasite. In this case, the conceptacles which hitherto bore the 

 bodies, figured as i and 2, are filled with club-shaped, colorless sacs 

 or asci, each of which usually contains eight reproductive bodies, 

 termed sporidia. The sporidia also germinate readily in the spring, 

 but, as already shown, the fungus has the power of propagating 

 itself in other ways, so that the sporidia are not absolutely essential to 

 the development of the parasite, at least for one year. It is very prob- 

 able that the sporidia arc designed to preserve the life of the fungus dur- 



