Gr. M. Thomson. — On the Origin of the New Zealand Flora. 497 



branches and branchlets reduced to spines ; but the genus is wide-spread in 

 the southern hemisphere, and our species is almost identical with an Aus- 

 tralian one. So strong a case cannot be made out with regard to Aciphylla, 

 or spear-grass, whose leaves and bracts are all spinous, and constitute a 

 most powerful means of defence. The genus is certainly found in AustraUa, 

 but the spines are not developed to any extent in the Australian species, 

 while our bayonet-leaved species are endemic. Hymenanthera, with exces- 

 sively rigid branches, and Eryngium, with spinous leaves and bracts, are 

 both genera which range into Australia, in the latter case the species being 

 identical. The same remark applies to many of our harsh cutting-grasses 

 or sedges, belonging to the genera Cladium, Gahnia, Lepidospernia, Carex, 

 etc., all being genera having wide distribution outside of New Zealand, and 

 some having identical species in Australia. Again we have apparent anoma- 

 lies in Dmcophyllum, with its pungent-tipped leaves (a character common, 

 however, to the Australian species), and in Desmoschcenus, the common, 

 large, scabrid sedge of our sand-hills. Very few species have the fruit pro- 

 tected against grazing animals. The only cases I know of are Sicyos angic- 

 latus, of which the nut is covered with barbed spines, but which is a species 

 common to Australia and parts of America ; and Entelea arborescens, with a 

 spinous capsule. This last plant is probably descended, after much modifi- 

 cation, from a stray immigrant of a remote period, its nearest ally being 

 Sparmannia, a Cape of Good Hope genus. 



Even the following facts, slight and almost unappreciable as they are, 

 tend to show that the absenee of grazing animals tends to modify species to 

 a considerable extent. We have in New Zealand two species of manuka 

 (LeptospermumJ ; of these, L. seoparium, with pungent tips to its leaves, 

 also occurs in Australia; L. ericoides, which wants the prickly tip, is endemic. 

 Similarly there are two species of Leucopogon, of which L. frazeri, with a 

 short spine or mucro at the apex of the leaf, occurs in Australia, and L. 

 fasciculatus, with smooth leaves, is endemic. Lastly there are five heaths 

 of the genus Archeria ; of these, two occur in New Zealand and one in Tas- 

 mania, all having obtuse leaves ; the other two occur in Australia, and have 

 very acute almost spinous leaves. 



The next matter bearing on this subject to which I now request your 

 attention is the relation of our flora to that of Australia, as pointed out by 

 Mr. Wallace in his latest theory, which is, that New Zealand was at one 

 time connected with the Asiatic region by way of tropical Australia, while 

 the whole of eastern Australia was an island separate from what is now 

 Western Australia by a comparatively shallow sea. This, he affirms, is 

 proven by the depth of the now intervening seas, by the geological forma- 



65 



