Explanation of IPlate. 



1. Section of a potato leaf magnified and showing the cells of the epidermis on the 

 upper and under sides, with two large hairs beneath, three threads of the mycelium 

 of the potato-rot fungus extending through the middle of the leaf, in the central por- 

 tion of which the cells have been purposely omitted to show the two resting spores and 

 the two smaller fertilizing bodies. From two of the mycelium threads, stems extend 

 down through a breathing pore on the underside of the leaf, one of which has two 

 lateral branches with conidia at the ends of them, while the main stem has an avoid 

 body at the end, from which the swarmspores are escaping. 



2. An avoid body much enlarged, the swarmspore showing within. 



3. A swarmspore much enlarged. 



4. A resting spore with its contents separating from the outside walls. 



5. A resting spore with its contents organized into swarmspores. 

 G. A resting spore burst and the swarmspores escaping. 



7. Three swarmspores swimming through the water. 



8. Three swarmspores having come to rest and their thread-like organs 

 disintegrated. 



9 and 10. Three swarmspores after having come to rest, developing mycelium 

 threads. 



