LIST OF ILLUSTRATIONS. 



PLATES. 

 PLATE 1. 



A. Wheat stoma wedged open by dust. 



B. Stoma of Rumex patientia. 



C. Epiderm of potato, showing stomata in all stages of development. 

 PLATE 2. 



A. Upper and lower epiderm of alfalfa. 



B. Upper and lower epiderm of potato. 



PLATE 3. Series 10, showing condition of upper (outer) and lower (inner) stomata of 

 potato at each hour of a 24-hour day,* together with the curves for sunlight, 

 temperature, and humidity. 



PLATE 4. 



A. Upper and lower epiderm of sugar-beet. 



B. Epiderm of onion. 



C. Epiderm of corn. 

 PLATE 5. 



A. Cross-section of alfalfa leaf, showing stoma and chamber. 



B. Cross-section of sugar-beet leaf, showing stomata and chambers. 

 PLATE 6. 



A. Cross-section of potato leaf, showing stomata, chambers, and air-passages. 



B. Cross-section of corn leaf, snowing stomata and chambers. 



PLATE 7. Series 11, showing upper and lower stomata of sugar-beet, and factors during 



a 24-hour day. 



PLATE 8. Series 16, showing stomata of onion, and factors during a 24-hour day. 

 PLATE 9. Series 16, showing lower stomata of corn, and factors during a 24-hour day. 

 PLATE 10. Control cabinets used for light experiments with stomata. 

 PLATE 11. Type of potometer used for stomata experiments. 

 PLATE 12. Series 28, showing upper and lower stomata of Fouquiera splendent, and 



factors during a 24-hour day. 

 PLATE 13. Series 32, showing upper and lower stomata of alfalfa from a heavily irrigated 



plot, and factors during a 24-hour day. 

 PLATE 14. Series 32, showing upper and lower stomata of cut stems of alfalfa, and factors 



during a 24-hour day. 

 PLATE 15. Series 33, showing upper and lower stomata of cow-beet in dry pots, and 



factors during a 24-hour day. 

 PLATE 16. Series 33, showing upper and lower stomata of cow-beet in moist soil, and 



factors during a 24-hour day. 



FIGURES. 



1. Three plants of alfalfa series 14, stripped for 27, 17, and 11 hours respectively, show- 



ing that the loss of a few leaves does not affect the stomatal movement. 



2. Series 1, showing movement in upper stomata of alfalfa and lower stomata of barley. 



3. Series 2, showing movement in upper stomata of alfalfa. 



4. Series 3, showing movement in upper stomata of alfalfa. 



5. Composite series 4-5, showing movement in upper stomata of alfalfa. 



6. Series 26, showing movement in upper stomata of alfalfa. 



7. Series 10, weather data for June 8-9, 1916. 



8. Series 10, showing movement in upper, lower, and stem stomata of alfalfa. 



9. Movement in upper stomata of alfalfa, showing change from day opening and night 



closure to night opening and day closure, as evaporation becomes more intense. 



10. Series 10, showing movement in upper and lower stomata of potato. 



11. Series 12, weather data for June 21-22, 1916. 



12. Series 12, showing movement in upper and lower stomata of potato and upper sto- 



mata of alfalfa. 



13. Series 20, showing weather data for August 25-26, 1916. 



14. Series 20, showing movement in upper and lower stomata of potato, plot 7. 



