4 NEW ZEALAND PLANTS. 



a rich, peculiar, and varied assemblage of plants came together in 

 a region so isolated as the New Zealand archipelago. This leads to a 

 second query, as to the origin of those special plants which are found 

 in no othei land. To answer these two questions at all fully is not 

 possible in the present state of knowledge ; still, some general idea 

 has been reached through the labours of New Zealand naturalists 

 and others. 



Let us in imagination peer into that remote past when New Zea- 

 land had finally emerged from the ocean, and when its surface, desti- 

 tute of all life, was ready to receive its plant and animal immigrants. 



Now, it is quite impossible to estimate geological time from figures. 

 When we try to think of millions of years, our minds become con- 

 fused ; and so those long periods during which the earth gradually 

 assumed its present form are designated by certain names representing 

 divisions of geological time. These have been classified according to 

 the fossils contained in the rocks. The divisions are five in number, 

 and are named respectively, beginning with the earliest the Archaean, 

 the Primary, the Secondary, the Tertiary, and the Quaternary or 

 Recent. These, again, are divided into smaller subdivisions, each, 

 however, still of an unthinkable age. 



With the first two great divisions we have nothing to do here. 

 The history of our plants commences at that subdivision of the 

 secondary period known as the Jurassic, when there flourished on 

 the earth in general cycads, ferns, horse-tails, and pine-trees. 

 The ancestors of the present crayfish and molluscs then lived 

 in the seas, and huge reptiles wandered through the moist forests. 

 Those plants which are propagated by means of the minute bodies 

 know T n as spores ferns and mosses, for instance are able to travel 

 vast distances by means of the wind, and, if the conditions are favour- 

 able, they soon gain a footing on unoccupied ground. Thus it is quite 

 easy to account for the presence of the same species of the lower groups 

 of plants in many lands far distant from one another. But when 

 one comes to deal w r ith the more highly organized seed-plants, whose 

 seeds could travel over a vast body of water only by the merest chance, 

 and w r ith animals in general, many of which are still less adapted for 

 ocean transit, speculations as to great changes having taken place on 

 the surface of the globe come into play, and former land-connections 

 betw r een regions now separated by the broad ocean have to be 

 assumed. 



