ANNUAL WINTER MEETING AT WARRENSBURQ. 245 



productive bodies of this form are one-celled, and stalked. Late in 

 the summer the same mycelium that has been sending up the one- 

 celled, stalked spores, gives rise to bodies that are one to many celled, 

 and are supported on distinct peduncles. These bodies fall to the 

 ground with the leaf, remain dormant during the winter and the fol- 

 lowing spring germinate and give rise to the cluster cups first described. 



The first stage is known as the jEcidiuin stage, and the spores 

 are called mcidiosporeS' ' 



The second is known as th6 If redo stage and the spores are 

 called uredospores. 



The spores of the third stage are called teleutospores and they are 

 the last produced in that season. 



There is usually another kind of reproductive organ present, 

 which has received the name spermagone. They are small, flask-shaped 

 bodies, filled with slender filaments. Some spermagonia evolve an 

 ■odor, and insects are occasionally attracted by this odor, which, ac- 

 •ccrding to De Bary, resembles the odor of orange flowers. Very little 

 is known, however, concerning the (spermagonia^ and they are useless 

 in the determination of genera and species. 



No doubt you are all familiar with the rust that occurs on the 

 leaves of the blackberry and raspberry. This fungus is known to bot- 

 anists as cacomma nitens. Very little is known concerning its life- 

 history, but as far as made out it is about as follows : 



The vegetative portion of the fungus appears in the tissue of the 

 host plant early in spring, and at length forms a dense felt-like mass 

 of threads. These threads ultimately give rise to an immense number 

 of globular bodies, which rupture the epidermis of the leaf and ap- 

 pear as orange-red postules. The globular bodies are the spores and 

 they are at first chained together, but soon after they rupture the epi- 

 dermis they are dispersed and may be found scattered over the surface 

 of the leaf. Under favorable circumstances each spore is capable of 

 producing a new plant, and when we take into consideration the im- 

 mense number of spores we can understand how rapidly the disease 

 may be propagated. If we compute 300 postules as occuring on each 

 leaf (and this is no unusual number), and suppose each postule to con- 

 tain 150,000 spores we shall have then 4,300,000 spores on one leaf. 



Only one stage of the rust is known, but no doubt the fungus is 

 only one form of one of the many rusts that occur later on. We only 

 know of one remedy for this disease and that is to dig up and burn all 

 infested plants. .Time expended in dusting the leaves with lime, ashes, 

 €tc., is little better than thrown away. 



