xxii LETTERS OF WILLIAM GRIFFlTtf. 



not agree with you as to Combretacese, which will be found to enter 

 Lindley*s Tubiferosse, which are generally a natural assemblage ; 

 its being petaloid is nothing, because all groups must pass into each 

 other at various points ; if not, there would obviously be no grada- 

 tions, and we might then took out as many do, for arbitrary cha- 

 racters. As you say, we want much more philosophy in our science : 

 is it not strange that while we knew of the existence grand divisions, 

 and had our minor divisions, i. e, families and genera, that we never 

 thought of intermediate ones until the appearance of Lindley's 

 Nixus, and in this they are not original, I intend studying Fries and 

 Agardh*s works ; I have seen somewhere that one or the other has 

 entered on that vital point, which is the most perfect plant ? and 

 has decided in favour of Compositae. There can be no doubt but 

 that Monopetalae are the typical form of plants ; this I shall try to 

 prove some day, but writing on abstruse points is thought pre- 

 sumptuous in young botanists ; besides such points require an ex- 

 tensive knowledge of structure I am glad you like Swainson, pray 

 also study his Geography and Classification of Animals ; it re- 

 quires no Zoological knowlege to master the main points, you will 

 see the superiority of his Geography over that of the Botanical 

 Geography of Schouw, who has too much frittered his divisions, 

 I don't know however whether Swainson has fairly proved five 

 Kingdoms, for South American must be divided from North. 

 The subject is a most difficult one, and to do it. any sort of 

 justice, requires that a competent person should be an universal 

 traveller. Then his 2 vols of Birds are models of what a Familias 

 et Genera Plantarum ought to be. Of the Geography and 

 Classification, part III. from p. 224 to 300 ought to be learnt by 

 heart by every botanist. You say in one part, that you think the 

 truly ternary orders should form a group or sub Kingdom, as 

 Gymnoperms, so they ought, provided Gymnosperms do form a 

 natural division, which they do not; for the solitary character 

 of having naked ovula is very insufiicient, and this insufiiciency 

 is proved by the small affinity existing between the component or- 

 ders. If you separate ternary orders, you ought to treat similarly the 

 binary, you can't do it, because by placing them all in one group, 

 you have no transition. Dicotyledonous groups must pass into mo- 

 nocotyledenous in an infinity of ways, both in modifications of the 



