186 



Transactions. 



The palisade layer is generally two cells thick, and about one-quarter 

 of the thickness of the leaf. The spongy parenchyma forms a rather deep 

 layer, and both it and the palisade layer contain abundant chlorophyll. 

 The cells of the mesophyll contain conspicuous oil-drops, usually one in each 

 cell. Bands of sclerenchyma occur at short intervals, extending from one 

 epidermis to the other, and also above and below the vascular bundles. 

 Pits can be easily seen in the walls of the sclerenchyma cells. The scleren- 

 chyma assumes a very bright tint with iodine-green or saffranin. Below 

 the vascular bundles of the midrib there are one or two canals. 



A study of the anatomy of this leaf reveals several xerophytic characters. 

 There is abundance of sclerenchyma, which makes the leaf very leathery. 

 The thickness of the cuticle, the possession of a double epidermis (probably 

 for water-storing purposes), and the great thickness of tomentum of empty 

 hairs on the lower surface, where the stomata occur, are all common in 

 plants adapted to dry situations. The position of the stomata above the 

 surface of the epidermis would seem to show that the hairy covering is 

 sufficiently effective in decreasing transpiration, and no further device, such 

 as sinking of the stomata, is necessary. 



Sections were made of leaves from garden specimens growing in an 

 exposed, sunny position. The only marked difference in the anatomy was 

 the far smaller amount of oil in the mesophyll of the garden -plant 

 than in that of the forest-tree. No different arrangement of chloroplasts 

 in the cells of the palisade layer could be detected, for in both cases 

 they seemed to occur throughout the cell, and not only on the walls. 

 (See figs. 6, 7, 8.) 



Griselinia littoralis Raoul. 



Griselinia littoralis Raoul, the broadleaf, is common in the bush and 

 in the open. There are some very ancient trees of this species on the hills. 

 One measured 4 - 75m. in circumference. It has large buttress roots. 



Fig. 9. — (a.) T.S. through leaf from a well-illurainated position on a tree of Griselinia 

 littoralis. (b.) T.S. through leaf from a young tree growing in a shady 

 position in the bush. Both x 60. 



Leaf-atwtomy. — This species grows into a comparatively large tree on 

 the hills, and the leaves are, as a rule, fairly well illuminated. Leaves 

 were taken and examined both from amongst those of a large tree and 



