lxxxvi FLORA OP TASMANIA. I On the JST. Zeal, and Polynesian 



the Mersey, to the Falls of the Meander, and westerly from Quaruby's Bluff to the Lobster Kivulet ; 

 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 Mr. 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 subalpiue, and is hence even less Australian 

 than that of all Tasmania is. The absence of all but four Rhamneee, the paucity of Restiacece, 

 Myrtacece, Liliacece, and Leguminosa, the abundance of Orchidea, Composites, and Epacridece, are 

 amongst the most noticeable features. 



§ 9. 

 On the Neiv 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 

 immigrants 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 ; 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 

 Fiji, Navigators', Friendly, and Society Islands to be represented by upwards of 140 genera of Thalamijlorce and 

 Calyeiflora (20S species). Only 26 genera are not Indian, and almost all of them are either new or confined to 

 these groups ; nor do I fiud one characteristic Australian plant amongst them, except a pliyllodineous Acacia. 



