206 PLANTS OF NEW ZEALAND 



Carmichaelia flagelliformis {Tlie Whip-like Carmichaelia). 



A slender shrul), 4 ft. in height. Leaves on young plants, .3-5-foliolate. 

 Young shoots much elongated, like whip-cord. Flowers usually fascicled, 

 3-7-flowered. Pod oblong, with short, stout beak. Seeds 2-4, flat mottled with 

 yellow or red. Both islands, local in the North. PI. Dec. -Jan. 



No genus is perhaps more characteristic of New Zealand 

 than this. The only representative outside these islands is the 

 well-named C. exsul of Lord Howe's Island. In Carmichaelia, 

 particularly in the dwarf species, the reduction of leaf surface 

 has been carried almost to the disappearing point. It is 

 probable that this reduction is due to an attempt to protect 

 the plants from loss of moisture, and not from expessive loss 

 of heat by radiation, as nearly all the forms of the genus are 

 glabrous. There is evidence to show that Carmichaelia was 

 originally a genus of leaf-bearing forest shrubs. C. exsul puts 

 forth its many tender leaves in the moist shade of the famous 

 palm-forests of the pictui'esque Lord Howe's Island. The 

 New Zealand species, compelled to live in the dry open plains, 

 develop leaves only in their early stages, or when growing in 

 shade. Some of the dwarf forms {e.g. C. Enysii''), never go 

 through a true leafy stage, but pass directly into a semi-leafy 

 form with flattened branches, and then into the leafless mature 

 form. They probably represent the last developed type of the 

 genus. The flattening of the branches, which is seen in most of 

 the species, is useful to the plant in various ways. It enables it 

 to obtain a larger accumulating surface, without exposing this 

 surface directly to the hot rays of the mid-day sun. Indeed 

 the chief advantage of a flattened stem over a leaf, for the 

 purpose of assimilation, is that the stem is in a vertical 

 position, and, therefore, transpiration from its surface will not 

 be so great as from the horizontal leaf-blade. Further, the 

 flattened stem gets the full light from the rising and setting 

 sun, when the heating effect is not excessive. In the closely 

 allied, scarcely distinct genus Corallospartium, the stomata are 



*Dr, Cockayne. Trans. XXXIII, p. 91. 



