WOODED STEMS. 



73 



Fig. 124. The tubers, or pseudo-bulbs, 

 of the SPIDER orchis. 



roots and leaves at intervals, and, in fact, forms new plants (Fig. 122). Such is the 



Strawberry (Fragaria). 



The Offset, as in the House-leek (Sempervivum 



tectorutri), is a short branch terminated by a cluster 



of leaves, and capable of independent existence 



after separation from the parent plant. 



The Hootstock, or rhizome, is a thickened root- 



ing stein, as in the Ginger (Fig. 123), and Iris, 



which produce young branches or plants yearly. 

 The Pseudo -bulbs of orchadaceous plants (Fig. 



124) very closely resemble tubers, except that they 



retain the marks of leaves which they once bore. 



They exist above ground, and contain amorphous 



starch. 



Wooded Steins. Having now offered such remarks on herbaceous stems (dis- 



tinguished from woody stems) as seemed to be required by their greater delicacy, we 



proceed to describe woody 

 stems and their appendages. 

 When treating of the mo- 

 difications of herbaceous 

 stems (page 59), we inti- 

 mated that such changes 

 also affected woody stems, 

 but in a lesser degree, and 

 shall therefore not again re- 

 fer to them under this head. 

 There are, however, a few 

 preliminary remarks which 

 are necessary as to the 

 general conformation of the 

 tree before we enter upon 

 an examination of the in- 

 ternal structure. 



The general divisions of 

 a stem are called branches 

 (nwm), and the arrangement 



*i&r?5&~~^ f '-~f3&s&&&a&mx nmrsrti ia^s^^eg?^ ^ them as a whole is termed 



corona, a head, as that of 

 a forest tree. (Figs. 125, 

 126.) "When they pro- 

 ceed from either side of the 

 stem, and then pass from the 

 base to the apex of the tree, 

 it is called a caulis excurrens, 

 but when the stems break 



Fig. 125. The BEECH TREK (Fagus), showing the corona, or head, 

 of forest trees. 



up into a mass of branches, it is known as a caulis deliquescens. Incompletely grown 

 Bhoots are termed innovations, and ramuli, or twigs, when very young. If the shoot is 

 long and flexible, it is called a vimen ; and when it proceeds from the stem at nearly a 



