14 Plant Moryhology . 



the stem from it. This is the one-half plan of arrangement as 

 expressed in the terms of phyllotaxy. If the rootstock were 

 straight there would be two rows of branches. Notice whether 

 these branches, if they should grow out straight from the root- 

 stock, would spread horizontally or vertically. 



Are the axillary buds, upon the lower side of the stem, as 

 strongly developed as those upon the upper side ? 



Strong fibrous roots are given off on all sides of the root- 

 stock, but most abundantly on the lower side. Notice the direc- 

 tion which all the roots take. 



The terminal bud is very hard in this plant and will often 

 penetrate objects of considerable firmness such as potato tubers 

 or other rootstocks when it comes in contact with them. It is 

 this power along with its persistency that makes it such a pest 

 to agriculturists. 



Sketch a rootstock (|) in the position which it occupies in the 

 soil, naming parts. 



Study the Underground Stems in the following plants : 

 Quack-grass (Agropyrum repens). 

 Canada Thistle (Cnicus arvensi.s). 

 Adder's Tongue (Erythronium Americanum). 

 Solomon's Seal (Polygonatum biflorum). 

 Trillium (Trillium grandiflorum). 

 Potato (Solanum tuberosum). 

 Indian Turnip (Arisaema triphyllum). 

 Onion (Allium sativum). 

 Lily (Lilium any species). 

 Bloodroot (Sanguinaria Canadensis). 

 Mandrake (Podophyllum peltatum). 



Read— Gray "Lessons" pp. 42-48. 



References — Gray "Structural Botany" pp. 56-84. 

 Bessey " Botany " pp. 159-165. 



