Thomson. — Botanical Evidence against Recent Glaciation of X.Z. 349 



found in the North Island ; (II) the absence of deciduous-leaved plants 

 in New Zealand ; and (III) the occurrence of a xerophytic or desert flora. 

 All these conditions demand an amount of time for their evolution much 

 in excess of that granted by any theory of Pleistocene glaciation. 



I. 



According to Cheeseman's Flora, there are 332 genera and 1,415 species 

 of flowering-plants in New Zealand. Of this number, two genera and forty- 

 five species are peculiar to the antarctic islands (Macquarie, Campbell, 

 Auckland, Antipodes Islands, and the Snares) ; while twenty-six genera 

 and 452 species are found in the South Island which do not occur in the 

 North Island. 



If we take the genera in detail, we find the two genera peculiar to the 

 antarctic islands to be more or less allied to others in the South Island. 

 Thus Stilbocarpa {Araliacece) , found in most of the islands, is allied to and 

 probably derived from Aralia, a genus found in the Snares and Stewart 

 Island, and in the south-west corner of the South Island. Of the three 

 species of Pleurophyllum, P. speciosum and P. criniferum occur in the Auck- 

 land and Campbell Islands, while P. Hooheri is also found in these groups 

 and in Macquarie Island. The genus is closely allied to Celmisia, " from 

 which it is separated rather by the very distinct and peculiar habit than by 

 any structural characters of importance." 



But when we examine the genera (nine of which are peculiar) found in 

 the South Island and not in the North, we meet with such diversity of struc- 

 ture and form that we are compelled to postulate long periods of time to 

 account for their great differentiation, or else our views of evolutionary 

 development are all wrong. 



Among the Cruciferce the genus Pachycladon, represented by one species 

 found only in the mountain regions of Central and West Otago, is quite 

 distinct from all other forms in New Zealand, and, indeed, is somewhat 

 peculiar in its characters, being " intermediate between the tribes Sisym- 

 briecB and LepidineceJ'' Another remarkable genus — Notothlaspi — has two 

 species singularly developed to resist drought. This genus also is quite 

 unlike any other. The genus Hectorella is n.ot closely allied to any other 

 genus of the order Portulacece, to which it belongs. Corallospartium crassi- 

 caule, the only representative of a remarkable genus of Leguminosce, is 

 allied to Carmichaclia, itself a genus peculiar to New Zealand (and Lord 

 Howe Island). Another peculiar type of this order is Notospartium, which, 

 though externally like Carmichaelia, differs in various points, such as its 

 many-jointed pod, a sort of character which does not probably arise by 

 gradual development from some other type. 



Among CompositcE the only genus confined to the South Island is 

 Ilaastia, a most remarkable group of four species of woolly-leaved plants. 

 Here we have not only a distinct genus, but four distinct species developed 

 since the separation of the Islands. 



Tetrachondra is a genus of one species (T. Hamiltoni), which has hitherto 

 only been found in the east and south of Otago. It is so anomalous in its 

 characters that systematists are not even agreed as to its position. Kirk 

 placed it in the genus Tillcea (nat. ord. Crassulacece) ; Oliver transferred 

 it to the BoracjinecB, among which Cheeseman also places it ; while Hallier 

 suggests that it should be considered an anomalous member of the Scro- 

 fhulariacecB, and that its nearest ally is the section Pygmaea of Veronica. 



