54 Transactions. 



The stomata occur chiefly on the upper surface, only an 

 occasional one on the lower : this is also for protection. 



Of hypoderm in the usual form of sclerenchyma there is no 

 trace, but certain large cells in the layer below the epidermis 

 have become modified to form tannin-sacs, more on the dorsal 

 or under surface than on the upper, where are most stomata. 

 These sacs also occur in great numbers around the xylem. 



The chlorophyll parenchyma is very homogeneous, consisting 

 only of larger and smaller parenchyma cells. 



The vascular bundles are much larger than those of the 

 totara cotyledons. This seems as if increased provision had 

 been made to carry a greater supply of water to make up for 

 the poorer protection against transpiration. Below the vascular 

 bundle we find two, occasionally one or three, resin-canals. The 

 presence of tannin-sacs was noted before. 



The xylem forms a well-marked group of centrifugal ele- 

 ments, and there are one or two isolated tracheids at the sides 

 of the bundle and on the ventral side of the wood. 



The phloem is also well developed, and, as in totara, there is 

 a crescent of crushed protophloem. These crushed elements 

 are separated by three or four rows of parenchyma cells from 

 the resin-canal. 



Hence we see that in most respects the cotyledon is simpler 

 than that of P. totara, but it will be noted that there is an in- 

 crease of vascular tissue in the bundle. 



Young Leaves. 



These were on the same plant as the cotyledon, and are from 

 J n in. to \ in. in length. They are very simple in structure. 

 In transverse section we note briefly : — 



Epidermal walls thicker than those of cotyledon, and cuticle 

 better developed. 



Stomata on both surfaces, but more on lower than upper. 

 Here the upper is the more exposed, not the lower, as in 

 cotyledon. 



Chlorophyll parenchyma differentiated. Upper palisade and 

 lower looser, some elongated towards margins. 



In the vascular bundle the chief difference from cotyledon 

 is the presence of a single resin-canal instead of two or three. 

 Tannin-sacs and transfusion tracheids occur. 



Plants approximately Two Years Old. 



These are from 6 in. to 7 in. high, and the leaves from \ in. 

 to £ in. in length. We note briefly : — 



The cuticle and epidermis more thickened than in previous 

 stage. 



