474 



ISLAND LIFE. 



[part. II. 



and abundant seeds must be dispersed by the wind almost as 

 readily as the spores of ferns. 



Another specialised group — the Scrophularineae, abounds in 

 New Zealand, where there are siKty-two species ; but though 

 almost all the genera are Australian only three species are so. 

 Here, too, the seeds are usually very small, and the powers of 

 dispersal great, as shown by several European genera — Vero- 

 nica, Euphrasia, and Liviosella, being found in the southern 

 hemisphere. 



Looking at the whole series of these Australo-New Zealand 

 plants, we find the most highly specialised groups — Compositse, 

 Scrophularinese, Orchidese — with a small proportion of identical 

 species (one-thirteenth to one-twentieth), the less highly special- 

 ised — Eanunculaceae, Onagrarise and Ericese — with a higher 

 proportion (one-ninth to one-sixth), and the least specialised — 

 Juncese, Cyperaceae and Graminese — with the high proportion in 

 each case of one-fourth. These nine are the most important New 

 Zealand orders which contain species common to that country 

 and Australia and confined to them ; and the marked corre- 

 spondence they show between high specialisation and want of 

 specific identity, while the generic identity is in all cases approx- 

 imately equal, points to the conclusioQ that the means of 

 diffusion are, in almost all plants ample, when long periods of 

 time are concerned, and that diversities in this respect are not 

 so important in determining the peculiar character of a derived 

 flora, as adaptability to varied conditions, great powers of multi- 

 plication, and inherent vigour of constitution. This point will 

 have to be more fully discussed in treating of the origin of the 

 Antarctic and north temperate members of the New Zealand 

 flora. 



Summary and Conclusion on the New Zealand Flora. — Confining 

 ourselves strictly to the direct relations between the plants of 

 New Zealand and of AustreJia, as I have done in the preceding 

 discussion, I think I may claim to have shown, that the union 

 between the two countries in the latter part of the Secondary 

 epoch at a time when Eastern Australia was widely separated 

 from Western Australia (as shown by its geological formation 

 and by the contour of the sea-bottom) does sufficiently account 



