Griffin. — Development of Neio Zealand Conifer Leaves. 55 



Stomata only on lower surface. 



Chlorophyll parenchyma, same arrangement as preceding 

 section, but more developed. 



Vascular bundle same as stage 1, only more elements. 



Succeeding Stages. 



In the succeeding stages we find a greater development of 

 cuticle, and there are a few cells corresponding to a hypoderm. 

 The number of transfusion tracheids is much increased, and the 

 vascular and chlorophyll cells much better developed. 



Though the maturer stages are better protected than the 

 younger, and have stomata only on the lower surface, yet we note 

 that in every stage of leaf there is an absence of a sclerenchy- 

 matous hypoderm, and that the middle parenchyma cells are 

 only very slightly elongated towards the margin, and there is 

 no lignification. In view of the difference of leaf-structure, 

 it is very interesting to compare miro with totara with respect 

 to habitat. As we should expect from the character of the 

 leaves, the totara is found in much more exposed conditions 

 than the simpler miro. The observations of the authoress 

 on their habitat have been confined to places north of Kotorua ; 

 but nowhere was the miro found in an exposed environment, 

 while the totara was frequently found where only the hardiest 

 of plants were surviving. 



Podocarpus spicata (Matai). 



This species is rare in this part, but is more common in the 

 South Island. I was unable to get any of the earliest stages 

 or of the mature, so I have not traced the course of development. 

 I found, however, plants about 2 ft. in height and young trees. 

 I will just indicate the structure of their leaves, since they are 

 to some extent intermediate between totara and miro. These 

 young trees are very hard to distinguish from miro, having the 

 same arrangement of leaves, and are also somewhat similar in 

 shape, but are blunter at the apex and whitish in appearance 

 underneath. 



Young Plants about 2 ft. high. 



This particular plant was growing in an exposed position, 

 and both its leaves and stem were coloured rather a bright- 

 bronze pink, the youngest leaves and stems pink, the older ones 

 more bronze-coloured. This is due to the presence of a pigment 

 in the cell-sap of the epidermal cells — perhaps anthocyanin — 

 and it is there for protective purposes. The leaves of this plant 

 were very short, and had blunt apices, which make the leaf 

 more oblong in shape. 



The anatomy is similar to that of miro : no hypoderm, 



