200 



Plant Physiology 



affecting their health injuriously, such as insect pests, 

 fungous diseases, general unfavorable environment, ac- 



FIG. 54. Abutilon, side view, under greenhouse illumination. 



cumulation of dust or soot thereon, means restriction of 

 their work in production. 



107. Respecting the distribution of chlorophyll. In 

 the higher plants the chlorophyll bodies may be disposed in 



