4'2'2 PLANTS OF NEW ZEALAND 



find one with an internal structiu-c similar to that of the 

 leaf of C. Li/allii. Probahly the large palisade cells were 

 insufficiently protected from transpiration, and hence the 

 adoption of the grass-like leaf. The stomata are in hair-filled, 

 longitudinal grooves, on the under surface of the leaf, and thus 

 the exposed transpiration surface is reduced to a minimum. 



We have liere, therefore, a remarkable example of the 

 principle, that the shape, and general appearance of the foliage, 

 depend to a. greater extent upon environment, and less upon 

 heredity, than is generally supposed. 



In C. se.^silifora the leaves are reduced to an inch or two in 

 height, and tire plant forms hroad masses surrounding the 

 flower heads, which are sunk amongst the apical leaves: and in 

 C. arf/fiitett the leaves have become needle-like and involute. 

 The leaves are also reduced to needles in C. lateralis and 

 C. lark I folia. It is such remarkable adaptations as these, that 

 have enabled Cehnisia to become one of the dominant genera 

 of the New Zealand sub-alpine meadows. 



Though so highly characteristic of mountain regions, the 

 genus IS also found on the lowlands, and by the sea-shore. 

 ('. longifulia, for example, in one of its mairy forms, is found 

 throughout New Zealand, from the sea-coast, up to the height 

 of about 5,000 feet. C. Madcaui, however, another very 

 distinct form, is only known with certaintj' from one spot on 

 Banks Peninsula. There, liowever, it is fairly plentiful, and 

 IS scarcely likely to suffer extinction, unless at the hands of 

 too enthusiastic collectors, so that perhaps it will be wiser not 

 to disclose the exact position of its habitat. 



Some of the Cclmisias, like many Olearias and other 

 Com[)osites, have varnished leaves. Some also closely 

 resemble the Andean Asters and Erigerons, and this, 

 doubtless, more l^ecause of similarity of habitat, than because 

 of aftinitv. 



