HYACINTH STEM 169 



letter V : it is more bulky than, but not so regular as, in 

 the Maize. The phloem lies between the limbs of the V- 

 The bundles are not sharply denned from the ground 

 tissue : very small bundles are scattered irregularly 

 towards the centre. Here and there may be found 

 cells with raphides. 



Longitudinal sections should also be cut, and a com- 

 parison made with the appearance of the tissues as seen 

 in the transverse sections. 



iii. STEM ARBOREOUS TYPE. 



I. Examine preparations of the old stem of Yucca 

 or Draccena, in which the thin-walled parenchyma 

 has been allowed to rot away, while the vascular 

 bundles remain. On comparing transverse and longi- 

 tudinal sections of such stems, it may be seen, with the 

 naked eye 



1. That the central primary bundles are isolated, 

 and that the course of each bundle may be traced as 

 starting from below at the periphery of the stem, then 

 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 

 immediately below the apical tuft of leaves : mount in 

 glycerine, and examine under a low power. Observe 



