G. M. Thomson. — On the Ongin of the Neiv Zealand Flora. 495 



is almost identical with a Puegiau species, and one or two with Tasmanian 

 forms. It appears to me probable that the singular Chatham Island Lily 

 (or Forget-me-not), Myosotidium nobile, is derived from an originally barbed 

 plant, and that by long isolation it has lost the barbed bristles on the 

 nuts characteristic of the Australian genus Cynoglossicm, its nearest allies, 

 just as it has lost the hispid character considered so distinctive of other 

 Boragine^. 



The last mode specified in which birds carry seeds, is — attached to the 

 mud or earth which clings to their feet. This subject has already been 

 so carefully and conclusively worked out, particularly by Mr. Darwin 

 in the " Origin of Species," that I need not do more than refer to 

 it. Sir J. D. Hooker, in the recently-published (1879) account of the 

 botany of Kerguelen Island (Challenger Expedition Keports), considers 

 that the few species of flowering plants of that island, presenting, as 

 they do, a decided Fugian facies, have been thus brought by land birds. 

 These are very abundant on the Falkland Islands, where the vegetation is 

 identical with that of colder South America, and favoured by the prevalent 

 westerly gales and the numerous stepping-stones, probably in the form of 

 islands formerly existing, these land birds have probably found their way to 

 Kerguelen Island. And he goes on to say that "the absence of such birds 

 from the present avi-fauna of the island offers no obstacle to such a specu- 

 lation, as such immigrants would on arrival speedily be destroyed by the 

 predatory gulls and petrels of the island." It is probable that some of the 

 antarctic and South American forms occurring in New Zealand, and also in 

 Tasmania and South-east Australia, have been thus introduced ; and this 

 probability is increased if we assume, with Mr. Wallace, that changes similar 

 to those which have occurred in the arctic regions have also taken place in 

 the antarctic, viz., that great alternations of climate have occurred in past 

 ages, during some of which the now ice-clad antarctic continent bore an 

 abundant flora of south-temperate forms, obtained probably from South 

 America, the nearest continental area. 



(3.) The third mode of plant-dispersion alluded to is by means of ocean 

 currents. This subject has also been carefully examined by Mr. Darwin, 

 and the results of his interesting experiments are detailed in the "Origin of 

 Species," and have been largely employed by Wallace in accounting for the 

 flora of oceanic islands, such as the Azores. I need not recapitulate these 

 results here, but will merely point out that the length of time during which 

 many seeds will float and retain their vitality, and also the probabilities of 

 such seeds being carried to localities suitable for their germination, are pro- 

 bably much greater than the popular idea would assign to them. In former 

 epochs, when there was a greater land extension, and, perhaps, a more tern- 



