BENTHAM ON THE SPECIES AND GENERA OF PLANTS. 149 



envelopes, we should have classed the latter among the essential organs 

 of the first class. 



The importance of characters, in as far as derived from the impor- 

 tance of the organs they relate to, would follow the same gradation, — ob- 

 servation (not theory) teaching us, however, to place those derived from 

 the reproductive organs of each degree before the corresponding ones 

 derived from the nutritive organs ; and those derived from the embryo 

 or young plant, more especially at the moment of germination, above all. 



But the second element in the ratio of value of characters, the 

 point of view in which the organs are considered, is one which experience 

 shows to be often far more important than the nature of the organ itself, 

 and the neglect of which contributes more than anything to the dege- 

 neracy of an apparently natural classification into a purely artificial one. 

 The principal characters which an organ, or set of organs, can thus sup- 

 ply, and their relative importance, are admirably expounded by De Can- 

 dolle, in his Taxonomie, div. I., chap. 3. He there establishes the fol- 

 lowing scale of gradation, in which I have ventured to make some slight 

 modification in expression, but which I think should never be lost sight 

 of by the systematist who has any pretension to establish natural 

 groups. 



1. The real presence or absence of organs (parts of organs, or sets of 

 organs), independent of adherence or accidental abortion. 



2. Their arrangement, or relative position, and numbers, as affecting 

 or indicating the general plan upon which the plant is constructed. 



3. Their external form, relative size, continuity or articulation, &c, 

 all subordinate to the preceding class, only acquiring importance when 

 indicative of a result from general arrangement. 



4. Their functions and sensible qualities, — the results, rather than 

 the causes, of the preceding modifications. 



By combining this scale of relative importance with that derived 

 from the nature of the organs themselves, it might be possible to frame a 

 general scale of relative importance of characters, which, with other 

 rules suggested by the observation of the comparative prevalence of 

 particular characters, might assist in judging of the expediency of de- 

 scribing as a new genus or order any newly-discovered plant which 

 does not come precisely within the limits previously fixed for any known 

 genus or order. But, in the grouping together any number of species 

 or genera already known, the relative value of the characters relied upon 

 should be tested, at every step, by a comparison with all the other fea- 

 tures of the plants. The blind adherence to a pre-established scale, in 

 distributing into genera the species of a large order, renders such a clas- 

 sification purely artificial. It had been ascertained that the relative 

 arrangement of the radicle and cotyledons in the embryo of Cruciferce, 

 the relative prominence of the ribs of the fruit, and the number and 

 arrangement of the vittas in Umlelliferce, the various modifications of 

 the pappus in Composite, were in many cases remarkably constant, not 

 only in species, but in many very natural genera. But by taking these 

 characters as absolute, and considering every slight modification of them 



