Cockayne. — Leaf-variation in Coprosma baueri. 343 



This latter character is frequently carried to such a pitch that 

 each half of the blade is rolled round itself, or the one half may 

 be rolled round the other, the leaf thus presenting the appearance 

 of a pipe. Such leaves may be called " rolled leaves." As for 

 the dimensions of the leaves, the following are taken from Island 

 Bay coastal plants: — (1) Leaves of the tree (laminae): 3-2 cm. 

 by 19 cm. ; 44 cm. by 2 - 4 cm. ; 4-5 cm. by 22 cm. ; 3*1 cm. 

 by 1*8 cm. ; 2-8 cm. by 1*6 cm. ; 5 cm. by 2 - 8 cm. ; 2-7 cm. by 

 1*5 cm. (2.) Leaves of the prostrate shrub (lamina?): 4 cm. 

 by 3-1 cm. ; 4 cm. by 2*8 cm. ; 34 cm. by 2 cm.; 3*8 cm. by 

 23 cm. ; 3 - l cm. by 2 cm. ; 4 - 3 cm. by 2 - 9 cm. ; 5 cm. by 

 3*3 cm. ; 2-6 cm. by VI cm. From the above figures it will be 

 seen that there is not much difference in size between the leaves 

 of the prostrate shrub and those of the tree ; perhaps, if a con- 

 siderable number of measurements were taken, the prostrate 

 plant, owing to the superior shelter from wind provided by its 

 habit of growth, would show a larger average leaf-surface. 



Turning now to the shade leaves of cultivated plants, some 

 of which it must be pointed out belonged to semi-sucker shoots, 

 they are much larger, slightly thinner, and not quite so glossy 

 as the leaves of normal coastal plants. Actual measurements 

 of various laminae read: 12/3 cm. by 9*7 cm. ; 1 1*8 cm. by 

 8-5 cm. ; 11-3 cm. by 8-8 cm. ; 12-8 cm. by 10-1 cm. ; 10*1 cm. 

 by 7 - 9 cm. Leaves from certain other shade shoots are not 

 quite so large, but still are much larger than the normal — 

 for example, the following : 6 - 5 cm. by 5'9 cm. ; 8 cm. bv 

 4 - 9 cm. ; 6 - 5 cm. by 5-8 cm. ; 6 - 9 cm. by 6 - l cm. From the 

 above it may be seen that the shade leaves, especially when 

 belonging to suckers, are frequently more than three times the 

 size of normal sun-and-wind leaves, and that they are always 

 -fiat, whereas the latter have always recurved and frequently rolled 

 leaves. 



Ordinary Coprosma hedges, such as are so common in the 

 City of Wellington, are especially instructive for purposes of 

 comparison, since they show all degrees of leaf-form from flat 

 leaves to those with considerably recurved margins. Generally 

 speaking, such hedges occupy more sheltered positions than 

 plants near the sea, and this shelter is frequently enhanced 

 by the hedge being on the lee side of a wooden fence of some 

 kind or another. In such hedges the leaves near the base are 

 more or less flat, becoming gradually more recurved towards 

 the summit of the plant, where they are exposed to the wind. 

 Even the uppermost parts of plants of considerable size, if shel- 

 tered from the prevailing winds, may possess some flat leaves. 

 Such hedges, moreover, possess few rolled leaves of an extreme 

 type, but are intermediate in character, so far as leaves are 



