GENERAL INTRODUCTION 29 



Amongst the dicotyledons, one of the oldest groups contains 

 the willow, poplar, oak, hazel-nut, birch, beech, chestnut, and 

 hornbeam. This group is highly characteristic of the Northern 

 Hemisphere, but though once well developed in New Zealand, 

 is now no longer represented here, except by the genus 

 Nothofagus, in which are included the " birches " of the sub- 

 alpine forests. The most highly developed family of plants, on 

 the other hand, is the Compositae ; and this, though almost 

 wanting in the bush, is well represented in the open country 

 and in the alpine and sub-alpine scrub by more than 230 

 species. There is, indeed, little if anything in the distribution 

 of the dicotyledons, to suggest that the New Zealand Flora is 

 older than the European. 



Again, it may be suggested that the large number of 

 green, inconspicuous flowers and the separation of the 

 sexes in an unusual proportion of the species are marks 

 of a primitive floral organization ; yet it is doubtful whether 

 they can be so interpreted. The former characteristic is 

 obviously to a large extent dependent on local conditions ; 

 for the foreign representatives of New Zealand genera with small 

 flowers have often large and showy blossoms. The New Zealand 

 species of Viola, Passiflora, Myosotis, and of the various genera 

 Orchidaceae have less conspicuous blooms than the corres- 

 ponding species in other lands. This lack of brilliancy of the 

 local forms, obviously cannot be due in all cases, to their greater 

 antiquity, but is much more likely to be the result of the 

 adjustment, or lack of adjustment, of the flowers to the insect 

 life of the country. The unisexual condition of many of the 

 flowers may be susceptible of a similar explanation. It is at 

 any rate not a primitive but a secondary condition, for it can 

 easily be shown that most of our dioecious plants were in quite 

 recent times hermaphrodite. In a word, the long isolation of 

 New Zealand has certainly resulted in the development therein 

 of many unique forms, and also perhaps in the preservation of 

 some antique types, yet it cannot be said there is a sufficient 



