lxxxiv FLORA OF TASMANIA. [Distribution of 



This catalogue places in a very strong light the thoroughly Eastern Australian character of the 

 Tasmania Flora : out of 1,063* species, only 280, or rather more than one-fourth, have not been found 

 on the Australian continent. There are only 22 genera and 267 species noted as being absolutely pe- 

 culiar to Tasmania, of which latter fully 44 will prove, in all probability, to be varieties. 



The contrast between the Floras of south-west Australia and Tasmania, in respect of their 

 affinity with that of south-east Australia, is very remarkable, for though their geographical contiguity 

 would lead us to expect that the Tasmanian Flora should be less different from the Victorian than 

 that of King George's Sound is, it must be recollected that Tasmania is placed several degrees 

 further south, in a colder climate and moister atmosphere, and is separated from Victoria by a wide 

 and deep oceanic channel. 



It will probably be conceded that Tasmania once formed a continuous southward extension of 

 Victoria, and that as Britain was peopled with continental plants before the formation of the 

 Channel, so Tasmania and Victoria possessed then- present Flora before they were separated by Bass' 

 Straits ; but if the effects of segregation and natural selection have done so little towards modifying 

 the Floras of the opposite shores during the immense epoch that has intervened since the earliest 

 formation of Bass' Straits, we are all the more puzzled to account for the complete change of the 

 south-western Flora, which is isolated by no such barrier from the south-eastern. 



There are only 592 flowering plants peculiar to Tasmania and Australia, or 860 if those peculiar 

 to Tasmania are included, so that fully one-fifth of the Flora is extra- Australian ; whereas only one- 

 sixth of the south-eastern Flora and one-tenth of the south-western are extra-Australian. Con- 

 sidering the before-mentioned isolation of Tasmania, this is certainly a most remarkable fact, and 

 requires a close scrutiny. 



Turning to the genera again, I find that out of the whole (394) , only 22 are absolutely peculiar 

 to Tasmania; or, adding these to the 122 which are exclusively Australian and Tasmanian, I find 

 only 144 in all. In other words, considerably more than two-thirds of the Tasmanian genera are 

 found in other countries besides Australia ; whereas in south-western Australia much less than half 

 the genera are extra- Australian, in south-eastern somewhat more than half, and in the whole Aus- 

 tralian Flora, between one-half and two-thirds. 



In examining the distribution of the genera and species a little further, I find that the deficiency 

 of Australian forms, and preponderance of extra- Australian, is caused partly by the paucity of new 

 genera of Australian affinity, partly by the absence of some that are common on the north shore of 

 Bass's Straits, but most of all by the greater proportion of New Zealand, South American, Ant- 

 arctic, and even European genera and species, some of which do not occur on the Australian 

 continent. Thus no less than 120, or nearly one-third, of the genera, and 67, or one-fifteenth, of the 

 Tasmanian species, are European, whilst with the other quarters it stands thus : — 



In all Australia, Europ. genera, one-sixth of the whole ; species about one-seventieth. 



In S.E. Australia „ less than one-third „ „ one-twenty-seventh. 



In S.~W. Australia „ less than one-fourth „ „ one-hundredth. 



In Tasmania „ one-third „ „ one-fifteenth. 



* These and the following numhers will not be found to accord exactly with the data on the preceding pages, 

 because, since the earlier sheets of the latter were printed off, I have received collections and notes from Archer, Gunn, 

 and Mueller, that slightly alter the number of the species, varieties, and then distribution. Slackhousia pulvinaris, 

 Muell. (see Vol. II. Suppl.), should be added at p. lx. ; " Australia " should be added to the distribution of Eryngium 

 tesiculosum (p. lxv.) and to Caloceji/iahis lacteus and the ten following species (p. lxvii.). " Isle of Pines " should 

 be expunged from 5S7. 



