64 



AGRONOMY 



In the green rose all the petals of the flower revert to leaves. 

 Stems are of most varied forms : in forest trees, tall, strong, 



and enduring for cen- 

 turies ; in the herbs, 

 low, weak, and lasting 

 but a single season. 

 In the crocus the stem 

 is reduced to a short, 

 thick, and solid mass ; 

 in the onion it is a 

 platelike disk at -the 



bottom of the bulb ; in the dandelion and the first-year plants 

 of many other species it is a collarlike organ at the top of the 

 root ; and in Solomon's seal and iris it is a thick, elongated, 

 subterranean, rootlike structure. In every case its chief func- 

 tions are to properly expose the leaves to the light and to 



FIG. 37. Conns of the gladiolus 



The right-hand figure shows the leaf bases re- 

 moved. The corin is a form of stem 





FIG. 38. The rootstock or rhizome of Solomon's seal 

 An underground stem. The dark spots are branch scars 



transport foods and food materials. Short-stemmed plants 

 gain illumination by spreading out their few leaves close to 

 the earth in rosettes ; others may send up a tall column with 

 many branches, upon which multitudes of leaves are hung; 

 while between these extremes are many different forms. 



