1868.] DRUMMOND — COMPARATIVE FLORAS. 431 



forms, is similar to that of Ontario and Quebec; that as the 

 Mississippi is approached there is a transition to a prairie flora 

 in some districts, and in others to the flora of the western plains 

 and wooded country ; that along the Atlantic coast there is a 

 maritime flora, some former members of which now occur in 

 special inland localities; that the line of distribution of many of 

 the United States plants has a north-westward trend ; and that 

 the Southern States have their semi-tropical species, many of 

 which do not range as far as, whilst others extend within, the 

 geographical limits of the Northern States. All these circum- 

 stances largely affect the number and character of the species in 

 each region. 



In our two Provinces there are representatives of one hundred 

 and fourteen natural orders. Of these Magnoliacese, Melasto- 

 niacese, Dipsacese, Bignoniacese, Pbytolaccacea3, Lauracess, 

 Ceratophyllacefe, Platanaceae, Amaryllidaceas, Commelynacese, 

 and Xyridacese, are, as far as known, confined to Ontario, No 

 order is, however, peculiarly provincial ; all have their represent- 

 atives in the Northern States among the one hundred and thirty- 

 two orders which embrace the flora of that section of the Union. 

 It is nevertheless a not uninteresting circumstance that, although 

 there are eighteen of these Northern States orders which have no 

 place in our Provincial flora, they comprise only thirty-five 

 species, most of which are Southern States forms. 



The geuera which have representatives in Ontario and Quebec 

 number 575, of which 428 are dicotyledenous, 124 are monoco- 

 tyledenous, and 23 comprise the filicoid plants. 



Of indigenous genera five are unknown south of the Great 

 Lakes. These are Cochlearia, Crepis, Armeria, Pleurogyne, and 

 Eheagnus, each of which comprises a single species. Crepis and 

 Elaeagnus are, with us, only found along the upper lakes, and are 

 probably entirely western in their distribution, whilst the remain- 

 ing three are of semi-arctic range. In addition to the above 

 there are some introduced genera, as Scabiosa, Tragopogon, Ajuga, 

 and Borago, which apparently have not been noticed in the 

 United States. Within the geographical limits of Prof. Gray's 

 work are 834 genera, 631 of which are dicotyledonous, 175 

 monocotyledonous, and 28 are filicoid. There are thus 263 genera 

 in the Northern States which are without either indigenous or 

 introduced representatives in either Ontario or Quebec. 



The relative numerical proportion of monocotyledonous and 



