64 Transactions. 



though not, as in kahikatea, towards the upper and lower sur- 

 faces. These awl-shaped leaves are, however, much longer 

 than those of the awl-shaped kahikatea, varying in length in 

 the younger stages from \ in. to t l in. in the mature. 



It would be a very interesting study to compare the rate of 

 growth of young plants of these two species of the same age, 

 and growing near each other under exactly the same conditions, 

 and thus find out which form of leaf — the shorter, flatter form 

 of the kahikatea, or the longer, narrower one of the rimu — is 

 more advantageous for plant-growth. 



Further differences will be noted in the more minute struc- 

 ture of the leaves in the various stages. 



Cotyledons compared with those of other Species. 



The cotyledons bear a great resemblance to those of miro 

 and kahi-katea, both in general shape and structure. 



The epidermal cells have thickened walls and cuticle, especi- 

 ally on the lower surface. This seems to be a general rule 

 among the cotyledons of the Podocarpeos, and probably of other 

 Conifers also, though I have not seen it remarked on. This is no 

 doubt due to the mode of germination. The young cotyledons 

 stay inside the seed for some time to absorb the food, and 

 hence the upper surfaces are pressed together and are thus pro- 

 tected, while the lower surfaces are exposed as soon as the 

 hypocotyl appears above the surface with the bases of the 

 cotyledons. 



The stomata also appear much more regularly on the upper 

 surface in the Podocarpece. In this particular species they occur 

 only on the upper surface, a position similar to that found 

 in the kahikatea cotyledon in its youngest stages, and in miro 

 they are more numerous on the upper surface. The fact that 

 the stomata are produced on the upper surface and then are 

 exposed when the cotyledons open out may, in some measure, 

 account for the fact that the cotyledons last for so short a time. 

 In the cotyledons of totara, which last for a considerable time, 

 we find great thickening of the epidermis on both sides, and 

 stomata, though they occur on both surfaces, are very much 

 greater in number on the lower. This provision for the future 

 is in accordance with the highly specialised character in other 

 directions. 



Hypoderm, as in miro and kahikatea, is absent. 



The chlorophyll parenchyma is homogeneous, like that of 

 miro ; and, like miro, tannin -sacs occur beneath the lower 

 epidermis and round the bundle. 



In the vascular bundle there is only rarely found a resin- 

 canal. These canals are not found universally in the cotyledons 



