186 CHLORIS MELVILLIAXA. 



notice, likewise, as a third cause of the delay, the greater 

 extent of my original plan, which included remarks on the 

 state and relative proportions of the primary divisions and 

 natural orders contained in the list ; a comparison with the 

 vegetation of regions of nearly similar climates ; and obser- 

 vations on the range of those species common to Melville 

 Island and other parts of the world. Towards the com- 

 pletion of this plan I had made considerable progress. But 

 to have satisfactorily treated some of the subjects referred to 

 would have required more time than I have had it in my 

 power to devote to them, and in several cases better 

 materials than I have hitherto been able to obtain. 



I have consequently found it necessary to relinquish, for 

 the present, this part of my plan,i and to confine myself to 

 a systematic list, adding only characters and descriptions 

 ccixiu] of the new or imperfectly known genera and species ; 

 the only indication left of my intention to treat any of 

 the subjects alluded to being a greater number of references 



' I sliaU here oifer a single remark on the relative proportions of the two 

 primary divisions of Phsenogamous plants. 



In my earliest observations on this subject I had come to the conolusion 

 that from 45° as far as 60° or perhaps 65° of north latitude, the proportion of 

 Dicotyledonous to Monocotyledonous plants gradually diminished. {Flinders' voy. 

 2, p. 538. Ante, p. 8.) But from a subsequent examination of the list of Greenland 

 plants, given by Professor Giesecke (Art. " Greenland," in Brewster's 'Edinburgh 

 Encyclopsedia'), as well as from what I had been able to collect respecting the 

 vegetation of alpine regions, I had supposed it not improbable that in still 

 higher latitudes, and at corresponding heights above the level of the sea, the 

 relative numbers of these two divisions were again inverted (Tuckey'a Congo, p. 

 423. Ante,f. 103); in the list of Greenland plants referred to,Diootyledones being 

 to Monocotyledones as four to one, or in nearly the equinoctial ratio ; and in the 

 vegetation of Spitzbergen, as well as it could be judged of from the materials 

 hitherto collected, the proportion of Diootyledones appearing to be still further 

 increased. 



This inversion in the cases now mentioned was found to depend at least as 

 as much on the reduction of the proportion of Graminese, as on the increase of 

 certain Dicotyledonous families, especially Saxifragese and Cruciferse. 



The Mora of Melville Island, however, which, as far as relates to the two 

 primary divisions of Phsenogamous plants, is probably as much to be depended 

 on as any local catalogue hitherto published, leads to very different con- 

 clusions ; Diootyledones being in the present list to Monocotyledones as five 

 to two, or in as low a ratio as has been anywhere yet observed ; while the 

 proportion of Grasses, instead of being reduced, is nearly double what has 

 been found in any other part of the world (see Humboldt, in 'Diet, des 

 Sciences Nat.,' torn. 18, table at p. 4] 6) ; this family forming one fifth of the 

 whole Phsenogamous vegetation. 



