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 



