CHAP. XXIII ARCTIC PLANTS IN NEW ZEALAND 523 



repeated several times during the Tertiary period, we have 

 no difficulty in understanding the general community 

 between the European and Antarctic plants found in all 

 south temperate lands. Kerguelen's Land and The Crozets 

 are within about the same distance from the Antarctic 

 continent as New Zealand and Tasmania, and we need not 

 therefore he surprised at finding in each of these islands 

 some Fuegian species which have not reached the others. 

 Of course, there will remain difficulties of detail, as there 

 always must remain, so long as our knowledge of the past 

 changes of the earth's surface and the history of the particu- 

 lar plants concerned is so imperfect. Sir Joseph Hooker 

 notes, for example, the curious fact that several Compositse 

 common to three such remote localities as the Auckland 

 Islands, Fuegia, and Kerguelen's Land, have no pappus or 

 seed-down, while such as have pappus are in no case com- 

 mon even to two of tl^tese islands. Without knowing the 

 exact history and distribution of the genera to which these 

 plants belong it would be useless to offer any conjecture, 

 except that they are ancient forms which may have 

 survived great geographical changes, or may have some 

 peculiar and exceptional means of dispersion. 



Proofs of Migration ly way of the Hiraalayas and South- 

 cm Asia. — But although we may thus explain the jDresence 

 of a considerable portion of the European element in the 

 floras of New Zealand and Australia, we cannot account for 

 the whole of it by this means, because Australia itself con- 

 tains a host of European and Asiatic genera of which we 

 find no trace in New Zealand or South America, or any 

 other Antarctic land. We find, in fact, in Australia two 

 distinct sets of European plants. First we have a number 

 of species identical with those of Northern Europe or Asia 

 (of the most characteristic of which — thirty-eight in 

 number — Sir Joseph Hooker gives a list) ; and in the sec- 

 ond place a series of European genera usually of a some- 

 what more southern character, mostly represented by 

 very distinct species, and all absent from New Zealand ; 

 such as Clematis, Papaver, Cleome, Polygala, Lavatera, 

 Ajuga, &c. Now of the first set — the North European 

 species — about three-fourths occur in some parts of America, 



