66 GENERAL REMARKS ON THE 



pans, and Ti/jjha cmgustifolia, which, though appearing to 

 differ in some respects from those of Europe, are probably 

 not specifically distinct. And if among the Plisenogamous 

 plants inserted there be any room for doubt respecting the 

 identity of the Austrahan and European species, it may 

 possibly be as to Arenaria marina, Zapanianodijlora, Atri- 

 plex Halimus, Potamogeton gramineum, Cgperus rotundus 

 and Holcus Gryllns. 



The first observation that occurs with regard to this list 

 is, that the relative proportions of the three primary divi- 

 sions of plants compared wdth tliose of the Australian Plora 

 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 Phsenogaraous plants of the list are, with very 

 few exceptions, also natives of North America, and several 

 of them are formd even in other parts of the world. 



There is nothing pecidiar 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 struc- 

 ture 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 consider- 

 able 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 Jcotyledonous or Cryptogamous orders it is 

 691] 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 Algte not 

 more than one sixth of the whole number found occur in 

 the list ; while of the Musci and Hepaticae one third, and 

 of the Lichenosse two thirds of those observed are also 

 natives of Europe. 



The proportion of European plants in Terra Austrahs, 



