4 PREFATORY REMARKS. 



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*, and to confine myself to a systematic list, adding only characters and descriptions 

 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 to authors 

 than is absolutely necessary for the present list, though essential to my original design. 



With this more limited plan, and with its execution, as far at least as regards the deter- 

 mination of several of the species, I am so little satisfied, that had the publication depended 

 entirely on myself, and related solely to the present essay, I should have deferred it still 



* I shall here offer a single remark on the relative proportions of the two primary divisions of 

 Phoenogamous Plants. 



In my earliest observations on this subject I had come to the conclusion that from 45° as far 

 as C0° or perhaps 65° of North Latitude, the proportion of Dicotyledonous to Monocotyledonous 

 plants gradually diminished. {Flinders' voy. 2. p. 538.) But from a subsequent examination of 

 the list of Greenland plants, given by Professor Giesecke, (Art. Greenland, in Brewster's Edinburgh 

 Encyclopedia) 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 ubovo the level of the sea, the relate numbers of these two divisions were again inverted; 

 (Tuchay'a Conrjo, p. 423.) in the list of Greenland plants referred to, Dicotyledones being to 

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

 Spitsbergen, as well an it could be judged of from the materials hitherto collected, the proportion of 

 Dicolylisdiiiics appearing to be still further increased. 



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

 reduction of the proportion of Graminere, as on the increase of certain Dicotyledonous families, 

 especially Snxifrivgem and Cruciferoo. 



Tlii! Flora of Melville Island, however, which, as far as relates to the two primary divisions of 

 PhBDnogninoitH plants, is probably as much to be depended on as any local catalogue hitherto 

 published, leads to very different conclusions; Dicotyledones being in the present list to Mono* 

 eolylcdones ns five to two, or in as low a ratio as has been any where 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. 416.) 

 this family forming one-fifth of the whole Phrenogamous vegetation. 



