EXPLANATION OF PLATE XXXH. 



Fig. 1. A spore of Macrosporium herculeum. 



Fig. 2. A cluster of sporophores of Helminthosporium incon- 

 spicuum, with one spore attached. 



Fig. 3. Spores of Septoria Helianthi. 



Fig. 4. Three uredo-spores of Puccinia Helianthi. 



Fig, 5. A teleuto-spore of Puccinia Helianthi. 



Fig. 6. From a photograph of a flat-turnip leaf affected with 

 Macrosporium herculeum. 



Note, — Figures 1-5 were drawn with the aid of the camera 

 lucida. Magnification, 345 diameters. 



