DESCRIPTION OF PLATES I to IV. 



(Phytophthora Colocasice Rac.) 



(Plate I was painted by K. Das ; the microscopical drawings were done in 

 pencil with the aid of the camera lucida by E. J. B., and copied in ink by K. Das.) 



Plate I. 



Lower figure : a leaf of Colocasia antiquorum Schott. severely attacked by 

 Phytophthora Colocasice Rac, viewed from above. 

 Upper figure : a young flower similarly affected. 



Plate II. 



Fig. 1. Surface view of a portion of a leaf of Colocasia ardiquoruw, bearing 



sporangia of Phytophthora Colocasice. X 320. 



Fig. 2. Infection of upper surface of Colocasia leaf by germinating zoospores. 



24 hours after inoculation. X 930. 



Fig. 3. Ditto, showing germ-tubes passing between the epidermal cells, not 



through them. X 930. 



Fig. 4. Emergence of a hypha through an epidermal cell of the under surface 



of the same leaf as in Fig. 3, third day after inoculation. X 930. 



Fig. 5. Part of a section of the corm of Colocasia, antiquorum, showing hypha- 



of Phytophthora Colocasia? both in and between the cells of the paren- 

 chyma and also in the vessels. X 200. 



Plate III. 



Fig. 1. Branching hyphw from a bean-agar culture at about the surface of 



the agar. X 330. 

 Fig. 2. Ditto from submerged mycelium. X 330. 



Fig. 3. Ultimate ramifications of submerged mycelium iu bean-agar. 



X 330. 

 Fiw. 4. Aerial mycelium bearing sporangia from a bean-agar culture. The 



sporangia are both lateral and terminal. At a. a branch arises just 



below a septum. X 330. 

 Fio\ 5. A group of sporangia from a strong bean-agar culture. X 330. 



Fi». 6. Irregularly shaped sporangia, the upper formed without stalk by 



lateral outgrowth of a hypha. X 330. 

 Fif. 7. Two sporangia with unusual types of insertion. X 330. 



