182 



HISTORY OF THE VEGETABLE KINGDOM. 



named, external characters so precise or so de- 

 cided as at once to disclose their resemblance to 

 certain others, recourse was had to analysis, and 

 it became necessary to search in all their organs 

 for modifications which might furnish char- 

 acters. 



The characters have to be considered with 

 reference to their value, their number, and their 

 affinity. 



With respect to their value, it wUl easily be 

 conceived that the characters derived from the 

 most essential organs of plants must be less 

 liable to variation, and more important than 

 those derived from other organs. Now, those 

 organs which conduce to reproduction, perform 

 the most important part in vegetable life, and 

 among them the embiyo, which is in a manner 

 the common end towards which aU the organs 

 of the plant direct themselves, is that which 

 occupies the first rank in importance. The 

 embryo, therefore, has supplied Jussieu with his 

 primary divisions. The stamina and the pistil 

 occupy the second rank, and afford more con- 

 stant and more valuable characters than the 

 floral envelopes. These characters are the more 

 fixed and important, that they are derived, not 

 fi'om the number and structure of these organs, 

 which are very subject to variation, but from 

 their relative position, which is fixed. Thus, 

 next to the embryo, the relative position of the 

 sexual organs, or their insertion, afl^ords the best 

 characters for the arrangement of plants. Lastly, 

 the stems, the leaves, and the roots, are all em- 

 ployed as accessory characters. 



With respect to their number, the characters 

 are associated, grouped, and arranged; and, from 

 the combination of simple characters, result 

 general characters, which serve to unite a certain 

 number of plants under a common denomina- 

 tion. 



Some characters are mutually connected, and 

 seem inseparable from each other. Those which 

 are derived from the flower and fruit are chiefly 

 of this kind. Thus for example, the inferior 

 ovary always implies a monosepalous calyx and 

 an epigynous insertion. A monopetalous corolla 

 almost always indicates that the stamina are in- 

 serted upon it, and that they have a determinate 

 number. 



From the value and importance which the 

 different characters possess, it is easy to see that 

 those least liable to vary ought to have been 

 employed for the fundamental divisions of the 

 vegetable kingdom. Thus the embryo has fur- 

 nished the first three great divisions in plants. 

 The stamina and the floral envelopes have after- 

 wards been employed for subdividing the first 

 three sections, which were established upon the 

 embryo. 



Jussieu's method is thus explained by Richard : 

 The plants that occur scattered over the surface 



of the globe constitute the individuals of the 

 vegetable kingdom. When we examine them 

 with attention, we soon perceive that in the 

 general mass there are numerous individuals, 

 which always present themselves to our view 

 under the same appearance, possess the same ex- 

 ternal and internal characters, and are always 

 reproduced under the same form. To all these 

 perfectly similar individuals, considered gene- 

 rally and abstractly, the name of species is given. 

 The species, then, is the aggregate of individuals 

 which are always reproduced in the same man- 

 ner. A seed produced by any given species al- 

 ways gives rise to an individual perfectly similar 

 to that from which it originated. The charac- 

 ters on which the distinction of the different 

 species from each other is founded, are generally 

 derived fi-om the organs of vegetation, that is, 

 from the leaves, the stem, and the roots. The 

 species which present some differences with re- 

 spect to the colour of their flowers, the place in 

 which they grow, and their relative height, con- 

 stitute varieties, which are distinguished from 

 species properly so called, by the circumstance 

 of their not being, in the natural state, repro- 

 duced from seeds with all their characters. Thus, 

 for example, the lilac usually has the flowers of 

 a delicate purple tint ; but its flowers are some- 

 times white, although none of the other charac- 

 ters have been altered. The white lilac, then, 

 is merely a variety of the purple lilac ; for if 

 seeds taken fi-om the white-flowered lilac are 

 sown, they give rise to individuals whose flowers 

 are indifferently purple or white ; which proves 

 that varieties are not always preserved by means 

 of seed. 



The genus consists of a greater or less number 

 of species, united by common characters derived 

 from the organs of fi-uctification, but all distin- 

 guished from each other by specific characters 

 peculiar to each of them, and furnished by the 

 organs of vegetation. Thus, the genus Anagallis 

 has for its characters a rotate monopetalous co- 

 rolla, five stamina, and a 'pyxidium for its fruit, 

 that is, a globular capsule opening in a circular 

 manner by a kind of lid. All the species of this 

 genus must possess these different characters; 

 but they are distinguished from each other by 

 the form of their stem and leaves. The other 

 genera are similarly constituted. 



If we bring together the genera in the same 

 manner as the species ; in other words, if we 

 place near each other all those which have com- 

 mon and similar characters, we form orders pro- 

 perly so called, if regard is had only to a single 

 character, such as the number of the stigmas, 

 the form of the fruit, &c.; and natural families 

 or orders, if we include all the considerations 

 that relate to the form, the structure, and the 

 relative disposition of all the organs of the plants 

 which we are an-anRinn-. 



