xl FLORA OF TASMANIA. [Tropical Flora. 



5. The sandstone table-land presents an arid, cheerless landscape, described by Dr. Mueller in 

 terms that apply perfectly well to the sandstone table-lands of the peninsula of India, and indeed 

 many of the characteristic genera are common to both. These consist of Terminalia, Melia, Cochlo- 

 spermum, Sterculia, Buchanania, Zizyphus, Nauclea, Baulunia, Indigofera, Erythrina, Gardenia, 

 Strychnos, Santalum, a profusion of Andropogoneous Grasses, and other shrubs and herbs, all of 

 which the Indian botanist recognizes at once as the prominent features of the sandstone ranges of 

 western Bengal, and central India. 



6. The sea-coasts are chiefly tenanted by an Indian vegetation, consisting of Avicennia, Rhizo- 

 phorece, Pandanea, Spinifex, Zoysia, Suriana, JEgiceras, Pemphis, Tribuhs, together with Colubrina, 

 Ipomcea, etc. 



To these Dr. Mueller adds, as a seventh region, the banks of the northern rivers, which, however, 

 seem scarcely to afford a peculiar vegetation. 



Other plants worthy of notice, as natives of tropical Australia, are a species of Musa and Ne- 

 penthes, both mentioned by M'Gillivray, who also is the authority for the occurrence of a clump of 

 Cocoa-nuts * on Frankland Island, for the Pomegranate on Fitzroy Island, and Caryota wens, at 

 Cape York. The same naturalist discovered Balanophora fungosa of New Caledonia at Rocking- 

 ham Bay, and no doubt there are many other plants of the Malayan and Polynesian islands still to 

 be detected in similar localities. 



The number of species in tropical Australia appears to be extremely small, owing, no doubt, 

 much to the dryness of the cliinate, and to the absence of any large rivers, swamps, and mountains ; 

 as also to the short duration of the rainy season, which in many parts of the coast lasts only from 

 November to January. Many discoveries may yet be anticipated, when it is considered how many 

 very common tropical Indian and Malay Archipelago weeds may be found to occur here and there 

 along the coast : but Brown spent many months on the tropical shores, and Cunningham several 

 years; Mueller traversed northern Australia, Armstrong resided some years at Port Essington; and 

 we have considerable collections from Bynoe, Mitchell, Bidwill, and M'Gillivray ; and it must hence 

 be doubtful whether future explorers •will raise the known number of 2,200 tropical flowering species 

 to much above 3,000. 



Mueller's collections alone contain, of plants collected between the Victoria River and Moreton 

 Hay, 1G0 Natural Orders, GOO Genera, and 1,790 Species, including Cryptogarnia ; but as the More- 

 ton Bay Flora can hardly be called Tropical, and as Mueller includes 14 Orders which scarcely ad- 

 vance north of the tropic of Capricorn, I must exclude, perhaps, 500 species, including Cryptogamia, 

 to work his results into my estimate, which includes 148 Natural Orders, 700 genera, and 2,200 

 species. 



The most extensive tropical Natural Orders are, — 



' Australia. 



Tropical Africa. 



India. 



West Indies.f 



Leguminosae. 



Leguininosa?. 



Legurninosas. 



Leguminosas. 



Graniuiete. 



Rubiaceae. 



Rubiacea_\ 



Compositae. 



Myrtaceae. 



Grain inea?. 



Orchideae. 



Rubiaceae. 



Conrposita?. 



Composite. 



Compositie. 



Gramineae. 



* Captain King (Toy. i. p. 194) mentions having picked up cocoa-nuts on the beach at Cape Cleveland; Flin- 

 der's (ii. p. 49) at Shoal-water Bay ; and Cook's party found old husks at the mouth of the Endeavour River. To all 

 these places the fruit or its remains was no doubt brought by currents. 



t Chiefly founded on Grisebach's Essay on the Plants of Guadeloupe, etc. 



