148 ORIGINAL ARTICLES. 



and systematic importance. The compounding these two applications 

 of the word is apt to lead into some fallacies. De Candolle, for in- 

 stance, after showing the impossibility of establishing any comparison of 

 relative importance in the functions of the organs of reproduction and 

 those of vegetation, but explaining why it is that the former practically 

 supply better characters than the latter, lays down the following scale 

 of progression in the importance of these reproductive organs : — 



1. L'embryon qui est le but de tout ; 



2. Les organes sexuels, qui en sont le moyen ; 



3. Les enveloppes de l'embryon ; 



4. Les enveloppes des organes sexuels ; 



5. Les nectaires ou organes accessoires. 



But, in the first place, the embryo in its perfect state can no longer 

 be called an organ of the parent plant. Until it is fully formed, it sup- 

 plies no characters. "When once formed, it has no function to perform 

 till it commences life as a new independent being. And this is the 

 great reason of the importance of the characters it then supplies. It is 

 a whole plant, not an organ of a plant. 



Secondly, the same arguments which show the impossibility of com- 

 paring the importance of the functions of the reproductive and vegeta- 

 tive organs, would apply to the flower (or ' les organes sexuels') and the 

 fruit (comprised in 'les enveloppes de l'embryon') — the apparatus for 

 producing the embryo and the apparatus for bringing it to perfection — 

 and, again, in the flower, between the male and the female organs ; for 

 all these are equally essential for completing the series of vital pheno- 

 mena which continue the species. It is true that, exceptionally, em- 

 bryos may be formed and brought to perfection without normal fertili- 

 sation, but so also the whole series may be dispensed with, and plants 

 are reproduced by buds without passing through the embryo state ; but 

 in all phanerogamic species, for their normal reproduction, the whole 

 series, the male organs, the female organs, and the organs of maturation, 

 are equally essential. 



Perhaps all that can be said of the relative importance of organs with 

 reference to their functions is this : That the so-called essential organs, 

 the sexual organs, and the organs of maturation among the reproductive, 

 and the perfect leaves or foliaceous surfaces, and the root-fibres among 

 the nutritive, stand first ; the protective organs, such as floral and fruit 

 envelopes, bud-scales, &c, occupy the second rank; and accessory organs, 

 including epidermal scales, are the lowest. But here again the relative 

 importance of these organs is not proved by a priori arguments, derived 

 from the necessity of their presence for performing those functions, but 

 from the observation of the degree of constancy of their being so em- 

 ployed. Cryptogamic plants have sometimes none, sometimes not all, 

 of the organs of the first degree; yet nutrition, fertilisation, and repro- 

 duction, take place, but by other means, with another class of organs. 

 And had we observed that, in phanerogamous plants, fertilisation of the 

 ovule never took place unless the sexual organs were enclosed in floral 



