THE STEM. 



23 



in its habit, and presents itself with more or less of the external 

 appearance of a root, of an enlarged fleshy bud, or of a combination 

 of these two. The leaves upon this are never green, but are of 

 fleshy or membranous texture and simple forms. Leaves of this 

 character are found on the outside of buds. 



2. The Leaf region, forming the ascending stem of plants gene- 

 rally, especially characterized by the green colour and great de- 

 velopment of the foliage. 



3. The Bract region, which is also known as the Inflorescence, is 

 distinguished by its smaller, more delicate, and sometimes coloured 

 leaves, the axillary buds of which produce flowers. 



The extent, both positive and relative, in which these regions are re- 

 presented is different in almost every plant ; but a few general statements 

 may be made serving to illustrate the subject. The leaf-scale region is 

 developed chiefly in herbaceous perennial plants ; and the principal modi- 

 fications of it will be examined below under the heads of Rnizomes, Bulbs, 

 and allied structures. It may be observed that the leaf-scales or abortive 



Fig. 13. 



Fig. 14. 



Diagram of a plant of Veronica hedercefolia, 

 where the leaf-scale region bears the coty- 

 ledons x, x, and the rest of the stem is a 

 true-leaf stem with flowers in the axils of 

 its upper leaves. 



Diagram of a plant of Veronica 

 Chamcedrys. The lower part is a 

 true- leaf stem, audits branches 

 are bract-stems or inflorescence?. 

 The roots proceeding from the 

 stem are adventitious. 



foliaceous organs are almost exclusively composed of the stalks or sheatbs 

 of leaves, without any part corresponding to the blade ; exceptions to 

 this, illustrating the rule, occur in tunicated bulbs like the Hyacinth 



