XXIV Journal o} Agricultural Research voi. vi 



Storage-Rots op Economic Aroids 



Page 

 Fig. I. Spores of different storage-rot organisms: A, Diplodia tubericola from 

 dasheen; B, Diplodia tubericola from sweet potato; C, Diplodia 

 gossypina from cotton; D, Diplodia sp. from Mangifera indica: 

 E, Diplodia maclurae from Toxylon pomiferum; F, Fusarium solani. . 552 



Larval Characters and Distribution op Two Species op Diatraea 



Fig. I. a. Average angle formed by imaginary lines through bases of setae of 

 Diatraea saccharalis crambidoides; b, average angle formed by imagi- 

 nary lines through bases of setae of D. zeacolella 622 



The Disease op Potatoes Known as "Leak" 



Fig. I. Microscopical appearance of Pythium debaryanum isolated from potatoes 

 affected with potato leak: a, Cell of a potato tuber showing fungus 

 filaments therein; b, oogonia and antheridia; c, mycelium; d, ger- 

 minating conidia 630 



Life Cycles op the Bacteria 



Fig. I. IMg. cycle oi Bacillus azotobacter. The broken straight lines divide the 

 different types of growth indicated by the letters A to M. The 

 Greek letters a to X refer to subdivisions. The single and double 

 pointed arrows indicate the development of one form from another. 

 The four circles confine, in every case, all those forms which repre- 

 sent together a rather constant mode of life and which have been 

 usually considered as bases for establishing separate species 678 



Mottle-leap op Citrus Trees in Relation to Soil Conditions 



Fig. I. Graphical presentation of the relationship between humus content of 



soil and percentage of mottled orange leaves 731 



2. Graphical presentation of the relationship between the ratio of organic 



carbon to humus in the soil and the percentage of mottled orange 

 leaves 734 



3. Graphical presentation of the relationship between the ratio of humus 



to lime in the soil and the percentage of mottled leaves 735 



4. Graphical presentation of the relationship between the mineral car- 



bonates in the soil and the percentage of mottled lemon leaves 737 



Agricultural Value of Impermeable Seeds 



Fig. I. Curves showing the rate of softening of impermeable red-clover seeds 



of different degrees of maturity 767 



2 . Curves showing the rate of softening and of germination of impermeable 



red-clover seeds of different lots 768 



3. Curves showing the changes in the permeability of seeds in wet blotters 



and in dr>- storage for various periods 773 



4. Curves showing the rate of softening of impermeable red-clover seeds 



under different temperatiu"e conditions 780 



5. Curves of the seedling production in the field in 16 to 18 days and of 



the germination in chamber in 8 days 787 



6. Ciurves of the seedling production in the field and of the germination 



in chamber in i2>^ months 790 



