170 PRACTICAL BOTANY 



that the arrangement of the tissues, as well as the 

 character of the vascular bundles, is similar to that in 

 the Maize : there is, however, a peripheral cortex, which 

 is not found in the Maize. Note that the cells of the 

 inner limit of the cortex are quiescent, and not under- 

 going division. 



III. Cut transverse sections of the stem of Dra- 

 caena at a point one foot or more from the apex, and 

 mount in glycerine. Examine with a low power, and 

 observe 



1. A well-marked epidermis. Beneath this 



2. A band of cork. 



3. A broad belt of cortical parenchyma, many 

 cells of which contain crystals (raphides, &c.). Here 

 and there a vascular bundle will be seen in the cortex : 

 these are bundles of the leaf- trace, passing inwards from 

 the leaves. 



4. At the inner limit of this the cells are not quiescent, 

 as in the yoiinger part of the stem, but there is an 

 actively dividing meristematic ring, which gives rise 

 internally to new vascular bundles, and externally to 

 fresh cortical cells. The new bundles thus formed are 

 cauline, having no direct connection with the leaves, 

 and are embedded in lignified ground-tissue. These 

 together form a dense ring. 



5. Centrally, there still remains undisturbed that 

 arrangement of thin-walled parenchyma and vascular 

 bundles which has been above noted in the young 

 stem as being similar to that in the internode of Maize : 

 the primary or common bundles may be distinguished 

 from the secondary or cauline bundles, not only by 

 their arrangement, but also by their structure, the latter 



