88 STRUCTURAL BOTANY. [73-75. 



root no such provision is made, and the branches have 

 a less definite arrangement. Now the growth of the 

 stem consists in the development of the internodes. 

 In the bud, the nodes are closely crowded together, 

 with no perceptible internodes ; thus bringing the rudi- 

 mentary leaves in close contact with each other. But 

 in the stem, which is afterward evolved from that bud, 

 we see full-grown leaves separated by considerable 

 spaces. That is, while leaves are developed from the 

 rudiments, internodes are pushed out from the grow- 

 ing point. 



221. There are, however, many species of plants, 

 especially of herbs, in which the axis of the primary 

 bud does not develop into internodes at all, or but par- 

 tially in various degrees. See the axis of Trillium, 

 Onion, and Bloodroot. Such stems seldom appear 

 above-ground. They are subterranean. This fact 

 makes a wide difference in the forms of stems, and nat- 

 urally separates them into two great divisions viz., 

 the Leaf-bearing Stems and the Scaled-bearing Stems. 



CHAPTER XYI. 



FORMS OF THE LEAF-BEARING STEMS. 



222. The leaf-bearing stems are those forms which, 

 with internodes fully developed, rise into the air 

 crowned with leaves. The principal forms are the 

 caulis, culm, trunk, caudex, and vine. They are either 

 herbaceous or woody. Herbaceous stems bear fruit but 

 one season and then perish, at least down to the root, 

 scarcely becoming woody ; as seen in Mustard, Radish, 



