Notwithstanding an identity of genera has been remarked upon their opposite shores, there are, nevertheless, certain others, frequent upon the East Coast, that appear wholly wanting on the north-western shores: of these, the existence of some, even in the tropical parts of New South Wales, seems governed by the primary formation of the coast, its mountainous structure, and consequent permanency of moisture in a greater or less degree; namely, almost all the genera of Filices, the parasitical Orchideae, Piper, Dracontium and Calladium (genera of Aroideae) Commelina and Aneilema, Calamus and Seaforthia, Hellenia a solitary Australian genus of Scitamineae, some genera of Rubiaceae, particularly Psychotria and Coffea, certain genera of Asphodeleae, as Cordyline, and a genus allied to it, whose fructification is at length obtained, a solitary plant of Melastomeae, and an individual Nymphea. Other genera also, but little influenced by those local circumstances of situation on the East Coast, that are excluded from the opposite shores, are Leucopogon (the only equinoctial genus of Epacrideae observed during the late voyages) the families Bignoniaceae, Jasmineae, the genus Erythrina, and of Coniferae, Araucaria of Norfolk Island. This absence of several orders of plants on the north-western shores, existing in New South Wales, or opposite coast, as well as the consideration (at the same time) of the evident causes of such a disparity of species on the former coast, would suggest the opinion, that such plants alone of other parts of the continent are indigenous to the North-west Coast, as are capable of sustaining themselves in a soil subjected to seasons of protracted parching droughts. This may apply to some species upon that coast, but it cannot be reduced to a general conclusion; for, on the one hand, it is singular so few of the plants of the South and South-west Coasts, and particularly that none other of their genera of Proteaceae (than those already mentioned) found altogether in an arid soil, should have been discovered throughout any part of its extensive shore; whilst, on the other hand, at a peculiar structure of a small and limited portion of that coast, in the vicinity of York Sound, a sufficiency of shade was observed to be actually produced by the unusually broken character of the country, to favour the nourishment and growth of certain plants alone to be seen beneath the shade of dense forests. These species were Myristica insipida, discovered by Mr. Brown, on one of the Prince of Wales group of islands on the North Coast; Cryptocarya triplinervis, Brown; bearing ripe fruit, Abroma fastuosa; and an undescribed Eugenia.