pæus, and Typha angustifolia, which, though appearing to differ in some respects from those of Europe, are probably not specifically distinct. And if among the Phaenogamous plants inserted there be any room for doubt respecting the identity of the Australian and European species, it may possibly be as to Arenaria marina, Zapania nodiflora, Atriplex Halimus, Potamogeton gramineum, Cyperus rotundus and Holcus Gryllus.
The first observation that occurs with regard to this list is, that the relative proportions of the three primary divisions of plants compared with those of the Australian Flora are inverted: for of 2900 Dicotyledones of the Flora only 15 are natives of Europe; while of 860 Monocotyledones 30, and of 400 Acotyledones upwards of 120 appear in the list.
The Phænogamous plants of the list are, with very few exceptions, also natives of North America, and several of them are found even in other parts of the world.
There is nothing peculiar in the apparent structure or economy of the Dicotyledonous plants common to countries so remote to account for their more general diffusion; though several of them grow in wet or marshy ground, yet very few are properly aquatic plants; and in the structure of their seeds the only circumstance in which they all agree is in the plumula of their embryo not being evolved.
Of the Monocotyledones, on the other hand, a considerable number are aquatic plants; and the greater part of those that are not aquatic belong to the irregular tribes, supposed to have a simpler structure.
Among the Acotyledonous or Cryptogamous orders it is 591] remarkable that there should be but a single species of Fern in the list, though those of the Flora exceed 100, of which 28 species are found likewise in other countries. It is also worthy of notice that of the Submersed Algæ not more than one sixth of the whole number found occur in the list; while of the Musci and Hepaticæ one third, and of the Lichenosæ two thirds of those observed are also natives of Europe.
The proportion of European plants in Terra Australis,
