Oliver. — Vegetation and Flora of Lord Hone Island. 



99 



habitat, and thus the effect of the habitat is shown by the minute structure 

 of the leaf, though probably only the specific differences in the endemic 

 species are due to the direct effect of the environment. 



Brieflv. the chief features presented by the leaves of the principal 

 forest-trees are (1) the presence in most species of a cuticle. (2) the frequent 

 occurrence of water-tissue consisting of two or three layers of large cells 



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Fig. 2. — a, Goprosma putida : b, Baloghia lucida ; c, Cryptocarya Gregsoni. 



beneath the upper epidermis, and (3) the dorsiventral arrangement of the 

 tissue of the mesophyll. the chief exceptions being Drimys howeana and 

 Randia stipulosa. 



So far as one can judge from the leaf-structure, most of the trees of 

 Lord Howe Island have devices for conserving water. This is perhaps 



Fig. 3. — a, Negria rhabdothamnoid.es ; b, Dracophyllum Fitzgeraldi ; c, Rapanea 



platy stigma. 



necessary on account of the frequent winds, which must have a consider- 

 able desiccating effect on the foliage. 



The cuticle is especially thick in Ficits columnaris, Acicalyptus Fnllagari, 

 and Hemicyclia australasica, three of the dominant trees in high forest. 

 There is also a thick cuticle in Metrosideros nervulosa and Baloghia lucida, 

 two shrubs widely separated systematically, but agreeing in this particular 



