Apr, i-sept. IS, 1921 Illustratiofis VII 



EifPEcT OF Reaction of Solution on Germination of Seeds and on 

 Growth op Seedlings 



Text Figures 



Page 



1. A, graph showing the relation of reaction to the contents of HjCgHjOy and 



NaOH employed in the cultures of series A; B, graph showing the change 



of reaction found after 4 days' growth of wheat seedlings in series A. . . 76 



2. A, graph showing the change in reaction obtained by electrometric titration 



in series B; B, graph showing the change of reaction found after 4 days' 

 growth of wheat seedlings in cultiu-es of series B 77 



3. Graph showing the relation of growth of wheat seedlings to reaction in 



series A 79 



4. Graphs showing the relation of growth of wheat, soybean, com, and alfalfa 



seedlings to reaction in series B 81 



5. Graphs showing the relative weights of sprouts produced by seeds of wheat, 



com, soybeans, alfalfa, and red clover in 7-day germination period at 

 various reactions 89 



Plate 



15. A. — Method of growing wheat seedlings. B. — Appearance of wheat seed- 



lings in series A at time of harvesting. C. — Appearance of wheat 

 seedlings in series B at time of harvesting 96 



Philippine Downy Mildew op Maize 



Text Figures 



X. Graph showing variation in length of conidia of Sclerospora philippinensis . . 11 1 



2. Graph showing variation in diameter of conidia of Sclerospora philippinensis . 11 1 



3. Diagram showing ratios of length to vsddth of conidia of Sclerospora philippi- 



nensis, arranged in classes and indicating limits of variation and mode. . 11 1 



Plates 



A. Young maize plant, showing the effects of a very early attack of the downy 



mildew on a small, early maturing variety, Manobo Yellow 122 



B. Young maize plants, showing the effects of later attack of the downy mil- 



dew on a large, late-maturing variety, Guam White Dent 122 



16. A. — Portion of a field of Moro White maize, showing heavy loss from the 



downy mildew. B. — View near the edge of a field of Guam White Dent 

 maize, showing the ravages of the downy mildew 122 



17. A. — A frequently encountered type of downy mildew effect. B. — A serious 



case of downy mildew injury, one of hundreds in a badly attacked maize 

 field 122 



18. A. — A common result of downy mildew attack. B. — A maize plant seri- 



ously injiu-ed by the downy mildew stands in front. C. — One hill in a 

 maize plot which lost heavily from attacks by the downy mildew 122 



19. A. — A case of abnormal growth of a maize plant as the result of an attack by 



downy mildew. B.— A maize plant which, when nearly mature, became 

 infected by the downy mildew through a small sucker previously devel- 

 oped 122 



20. A. — A deformed and partly sterile ear complex produced by a maize plant 



as a result of downy mildew infection. B. — A maize ear developed 

 abnormally as a result of the downy mildew. C. — Ear of a maize plant 

 infected by the downy mildew 122 



