V. ROOTS AND UNDERGROUND STEMS 



FUNCTION AND STRUCTURE OF ROOTS 



Material. — Two earthen pots, with a growing plant in one. Some 

 coarse netting, a common tumbler, and sprouting seeds of mustard, or 

 other easily germinating kind. A stallc with roots, of corn or any Icind 

 of grass, and one of cotton or other woody plant. A woody taproot 

 inserted in red inlc from four to six hours before the lesson begins. 



164. Roots as Holdfasts. — One use of ordinary roots is 

 to serve as props and stays for anchoring plants to the soil. 

 Tall herbs and shrubs, and vegetation generally that is 



236. — Dandelion : u, common form, grown in plains region at low altitude ; 

 b, alpine form. 



exposed to much stress of weather, are apt to have large, 

 strong roots. Even plants of the same species will develop 

 systems of very different strength according as they grow 

 in sheltered or exposed places. 



165. Root Pull. — Roots are not mere passive holdfasts, 

 but exert an active downward pull upon the stem. Notice 

 the rooting end of a strawberry or raspberry shoot and 

 observe how the stem appears to be drawn into the ground 



