THE SNAP-DRAGON FAMILY 



373 



of HeUcJirtjsum belonging to the sub-genus Ozothamnus (v. fig. 

 1'21). A partial clue to their origin is to be found m the fact 

 that all species of this section, under certain circumstances, 

 put forth leaves of a type, widely distinct from, and much 

 more normal, than the scale-like plates with which they are 

 usually covered. A similar phenomenon appears in many 

 other aberrant plants. Otlier New Zealand species which 



Fig. 1-23. 1. V. propinqua. 2. V. tetrasticha. 3. V. Hectori. 4. V. .Vviiistrongii. 

 .5. V. elliptica. 6. V. epacridea. 7. \. cupresHoides. 



■show a like heterophylly, as it may be termed, are 

 Helichrysum (Ozothamnus) coralloides, Baoidla bryoides, and 

 JRaoulia mammillaris. There can be but little doubt that, in 

 each case, the larger leaved form is the ancestral one. It 

 may therefore be expected, in accordance with the ordinary 

 law {v. p. 256), that the seedling form in its development 

 would pass through a stage with large leaf-surfaces. Such 

 a stage is often termed a " reversion shoot." Keversions 



