68 



PLANT STUDIES 



48. Relation to light. — As stems bearing foliage leaves 

 hold a siteei.'d relation to light, it is necessary to speak of 

 the influence of light npon the direction of growth, an 



Fiu. 59. All fliii in SiAnv^v, Bliowiiif,' the brcakiiiL- up ni ii,, umik 

 the spreading' top. 



influence known as heliofrapism, already referred to under 

 f(.lia,ge leaves. In the case of an erert stem the tendency 

 is to grow towards the source of light (see Figs. 1, (U). 



