STEM. ARBOKEOUS TYPE. 113 



curving towards the centre as it ascends, and finally 

 turning outwards, and passing into a leaf. These are 

 therefore common bundles. 



2. That the peripheral mass of secondary bundles 

 increases in thickness towards the base of the stem, 

 and has no direct connection with the leaves. These 

 bundles are therefore cauline. 



II. Cut transverse sections of the stem of Draccena 

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

 in glycerine. Examine with a low power, and ob- 

 serve 



1. A well-marked Epidermis. Beneath this 



2. A band of Cork (cf. Elm). 



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 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 (i.e. 

 have no direct connection with the leaves), and are 

 embedded in lignified ground tissue. These together 

 form a dense ring. 



5. Centrally, an arrangement of thin-walled Paren- 

 chyma and Vascular bundles, similar to that in the 

 internode of Maize. 



Note the passage of these central bundles outwards 

 to the bases of the leaves. They are common bundles. 

 Note also the mode of formation of the cauline 

 bundles (cf. Hippuris). 



