1XXXV1 FLORA OF TASMANIA. [On the N. Zeal, and Polynesian 
the Mersey, to the Falls of the Meander, and westerly from Quamby's Bluff to the Lobster Rivulet ; 
the whole comprising an area of about 400 square miles. 
The rocks of the northern part of this tract, including Mount Gog, are chiefly quartzite ; and 
the remainder, including a portion of the Western Mountains, elevated fully 4,000 feet, are for the 
most part basalt. Immediately above Cheshunt, to the south-west, rises an offset of the western 
mountains, named Cumming's Head, along the north-east base of which extends a tract of sandstone 
and fossiliferous limestone, which is the habitat of nearly all Air. Archer's cryptogams. 
This district has already produced nearly 550 flowering plants, or rather more than half of all 
that are known to inhabit Tasmania. The character of the Cheshunt Flora is, on the whole, that of 
a cold hilly region, approaching, in many respects, to the subalpine, and is hence even less Australian 
than that of all Tasmania is. The absence of all but four Rhamnea, the paucity of Restiacece, 
Myrtaceee, Liliacecs, and Leguminoste, the abundance of Orchidete, Composite, and Epacridete, are 
amongst the most noticeable features. 
§ 9. 
On the New Zealand and Polynesian features of the Australian Vegetation. 
I have already remarked that these features, in so far as they are peculiar, are confined to the 
east and south-east coasts of Australia, and chiefly to the temperate regions, including Tasmania. 
There is a great difference between the temperate and tropical Floras of eastern Australia in respect 
to the character of their non-endemic genera and species, for the former appears to have received 
mmigrants from New Zealand and the Antarctic regions, whilst the latter contains an assemblage of 
forms common to itself, India, and the Pacific. There is, however, no evidence in either case that 
the migration has been in one direction more than in another : Tasmania may once have been peopled 
by New Zealand and antarctic forms, before the Australian vegetation spread over it and replaced 
these ; and Australia itself may have derived its peculiar features from some Pacific islands which 
have since been overrun by an Indian vegetation. I have therefore not subdivided this Section, 
but shall regard the affinities, both tropical and temperate, under the same point of view. 
To the eastward of Australia are various groups of islands so arranged as to form a sort of rude 
outlying girdle to that continent. Beginning from the northward, these are the Solomon's Islands, 
New Hebrides, New Caledonia, Norfolk Island, and the New Zealand group ; to which might be 
added Eastern New Guinea, the Louisiade Archipelago, and New Ireland, but I know very little of 
their botany. 
The common botanical feature of all of these archipelagos, that lie to the north and east of the 
New Hebrides, and indeed of all the Polynesian groups westward of Juan Fernandez and the Gala- 
pagos (which are wholly American), is that they are peopled mainly by Indian and Australian genera, 
and in a very slight degree by American j but these Floras (Indian, Australian, and American) are 
represented in very different proportions in different groups; and I have observed (note at p. xvi.), 
that there are in this respect considerable anomalies in the Floras of contiguous archipelagos, those 
immediately to the eastward of New Caledonia* being remarkably deficient in Australian genera. 
* In the only published volume of Asa Gray's 'Botany of Wilkes's Exploring Expedition,' I have found the 
Bdly, and Society Islands to be represented by upwards of 140 genera of tkalamfior* and 
Cahjcifiorm (208 species). Only 26 genera are not Indian, and almost all of them are either new or confined to 
these groups ; nor do I find one characteristic Australian plant amongst them, except a phyllodineous Acacia. 
