46 Transactions. 



The drawings have all been done with the aid of a camera 



lucida. 



Classification of Species taken. (Engler.) 



Group . . . . • • Taxace^;. 



Subgroup . . . . . . Podocarpe^e. 



Genera . . . . . . Podocarpus and Dacrydium. 



Species — 



1. Podocarpus totara (totara). 



2. ,, ferruginea (miro). 



3. „ spicata (matai). 



4. ,, dacrydioides (kalrikatea). 



5. Dacrydium cupressinum (riimi). 



6. ,, Kirlcii. 



Podocarpus totara. 



The leaves of this species have been chosen as an intro- 

 duction to this genus on account of their simple but well-marked 

 transitions, which all point to the greater adaptation of the 

 maturer plant to surroundings which call for a xerophytic habit. 

 With the exception of young plants with cotyledons, all the 

 leaves of the different stages were gathered within not so many 

 yards of one another. 



Young Plants with Cotyledons. 



The cotyledons of this species are interesting, for they re- 

 main much longer on the plant than they do in other species 

 of this genus. They may be found on plants several inches 

 high, which have an appreciably thick and woody stem. There 

 is a marked development seen in the cotyledons on the older 

 plants from those on the younger. There is a general increase 

 in thickness of cuticle and epidermis for protection, and in- 

 crease of vascular tissue for conduction. This development is 

 best shown by a study of transverse sections of the two. 



Young Cotyledon, § in. long. — The epidermal cells are pro- 

 tected by a fairly thick cuticle, and have well-thickened outer 

 and side walls. 



The stomata occur on both surfaces, but more on the lower 

 than on the upper. They are only a very little sunk, and heme 

 very little overarched by neighbouring epidermal cells. There 

 is an air-space beneath each. 



The sclerenchymatous hypoderm is not developed except 

 just at the margins, where more protection is required. 



The chlorophyll parenchyma shows rather a high degree of 

 differentiation. At each margin of the leaf we find ordinary 

 parenchyma, the diameter of which is the same in all direc- 

 tions. Below the epidermis, on the upper side of the leaf, we 

 find cells more or less elongated at right angles to the surface, 



