304 PLANTS OF NEW ZEALAND 



have a case of initial endemism. Now it is often difficult to 

 say whicli explanation should be adopted, in a given case. 

 If the plant is closely allied to one existing on the mainland, 

 we probably have a case of initial endemism. If, however, 

 it belongs to a type not represented on the mainland, it is 

 more likely that we have to do with an example of relict 

 endemism : and that the species was once widely distributed, 

 and now, having been almost exterminated, finds a sanctuary 

 only in inaccessible localities and remote islands. In some 

 cases Palseo-botany comes in to give us assistance in solving 

 the problem. Thus, fossils show us that the genus Agathis 

 was once widely distributed, though now restricted to 

 Auckland province (where the Kauri is found), to the Malay 

 Archipelago, and to Queensland. Thus in the Kauri we have 

 a clear case of relict endemism. The older botanists, 

 however, generally neglected this method of explaining 

 restricted distribution, in favour of the hypothesis of initial 

 endemism. Tliere can, however, be but little doubt that 

 forms like the one under consideration, are more likely to have 

 been at one time widely spread, than always to have been 

 restricted to their present habitats. Though Stilbocarpa is a 

 genus endemic in these islands, yet it is closely connected 

 with the widely distributed genus Aralia. On the mainland, 

 StilhocariM is now confined to South-western Otago, but, as 

 it must have reached that district from the outside, it has 

 certainly, at one time, had a wider distribution. 



S. Lyallii sends out runners, which pass under stones 

 and through crevices in the rocks, rooting in suitable 

 localities. It is thus able to cover wide areas. This 

 characteristic also readily distinguishes it from B. 2)olarii<, 

 which is without runners. 



Genus No th op a 1 1 ax . 



A rema.rk.ible genus of shrubs or trees, showing much variation in leaf- 

 form. All the New Zealand species are endemic. Flowers in umbels, racemes, 

 or panicles, green, inconspicuous. Petals and stamens 5. Ovary '2-4-cellcd. 



