CH. Villi 



INVASIONS 



79 



These are bare and unvarnished facts, and though found bv 

 aid of the hypothesis of Age and Area do not depend upon it in 

 any way, but may be examined upon their own merits It is 

 clear from them that the previous distributional history of these 

 groups of genera must have been quite different, and it would 

 seem to pomt to the conclusion that the present flora of New 

 Zealand has been the result of at least three distinct invasions 

 ot plants from elsewhere, which probably had their centres at 

 the pomts, north, south, and central, where the masses of 

 maxima occur. 



This is confirmed by examination of the actual genera, for the 

 northern group is composed of families characteristic of Indo- 



Endemics 



^Malaya, probably indicating an invasion thence, the southern 

 group belongs to Ranunculaceae, Umbelliferae, and other 

 families prominent in the northern hemisphere (the only ex- 

 ceptions being Stylidiaceae and Centrolepidaceae, both southern 

 families), and the central group to Stackhousiaceae, Campanu- 

 laceae, Violaceae, etc., which may perhaps have come from 

 Australia. 



If now one add together all the species of the genera of the 

 northern invasion that occur at each zone of 100 miles from 

 north to south in New Zealand (including Stewart Island), one 

 obtains the curves shown above, from which one may peiiiaps 

 mfer that the invasion was at about 0-300 miles from North 

 Cape. The two curves fall off very steadily towards the south, 



