LINDLEY'S VEGETABLE KINGDOM 



41 



times unconsciously employcil by the superficial 

 observer, as when he calls all yellow tlowered 

 Composites Marig^olds, anil all whitc-flowereil ver- 

 nal bushes Thorns. It must be evitlent to the 

 ninst careless thinker that such resemblances are 

 trifling. That which really determines affinity is 

 correspondence in structure. It may be said that 

 hose plants are most nearly related which corres- 

 pond in the greatest number of points, and those 

 the most distantly in which we find the fewest 

 points of correspondence; and this must be true 

 when we remember that if every point in the 

 s'ructure of any two plants is found to be alike, 

 then those two must be identical. But it will be 

 obvious that an examination of all plants through 

 e\ery iletail of their organization is impracticable; 

 it has never in fact been accomplished in any one 

 case. Experience must have shown that the or- 

 gans of vegetation are of very difTerent degrees of 

 value in determining resemblance in structure; 

 that some are of paramount importance, others of 

 less consequence, and others of comparative insig- 

 nificance. Hence the relative value of characters 

 forms a most important part of the study of the 

 Eotanist; it is in fact the pivot upon which all the 

 operations of a systematist must turn. 



The only intelligible principle by which to esti- 

 mate their respective value is according to their 

 known physiological importance; regariling those 

 organs of the highest rank which are most essen- 

 tial to the life of the plant itself; placing next in 

 order those with which the plant cannot dispense 

 if its race is to be preserved; assigning a still lower 

 station to such organs as may be absent, without 

 considerable disturbance of the ordinary functions 

 of life; and fixing at the bottom of the scale those 

 parts, or modifications of parts, which may be 

 regarded as accessory, or quite unconnected with 

 obviously important functions. 



The first office which all organized beings have 

 to perform is that of feeding; for it is thus onlj- 

 that their existence is maintained. The second 

 is that of propagating, bj' means of which their 

 si>ecies is perpetuated. These being functions of 

 the highest importance, it is reasonable to conclude 

 that the organs provided for their jiroper execu- 

 tion must be of the highest importance also, and 

 hence that they are beyond all others valuable for 

 the purposes of classification. And again because 

 the j)ower of feeding must come before that of 

 propagating, it might be conjectured beforehand 

 that the organs destined for the former operation 

 would afford the first elements of a Natural method. 

 But since the action of feeding is very simple in 

 the Vegetable Kingdom, because of the similar 

 modes of life observable among jilants, while, on 

 the contrary, the act of propagation is highly di- 

 versified, on account of the very varied nature or 

 structure of the parts by which it is accomplished; 

 so might we conjecture that the organs of nutrition 

 would afford but few distinctions available for pur- 

 poses of classification, while those of fructification 

 would furnish many. And such is the fact. Hence 

 it is that the great classes of plants are principally 

 distinguished by their organs of growth, and that 

 in the numerous minor groups such peculiarities 

 are comparatively disregarded, their chief distinc- 



tions being derived from their parts of reproduc- 

 tion. These principles are more fully expressed 

 in the following axioms: — 



1. Peculiarities of structure which are connected 

 with the manner in which a plant is developed, are 

 physiological ; those which are connected with the 

 manner in which parts are arranged, are structural. 

 Physiological characters are of two kinds, viz., 

 those which are connected with the mode of growth 

 (the organs of vegetation), and those which regn- 

 \a.te reproduction (the organs of fructification). — 

 Physiological characters are of greater importance 

 in regulating the natural classification of plants than 

 structural. 



2. All modifications of either are respectively 

 important, in proportion to their connection with 

 the phenomena of life. 



3. If we allow ourselves to be steadily guided by 

 these considerations, we shall find that the internal 

 or anatomical structure of the axis, and of the fo- 

 liage, is of more importance than any other charac- 

 ter; because these are the circumstances which 

 essentially regulate the functions of growth, and the 

 very existence of an individual. 



4. That next in order is the internal structure of 

 the seed, by which the species must be multi|ilied. 

 Thus the presence of an embryo, or its absence, 

 the first indicating a true seed, the latter a spore, 

 are most essential circumstances to consider. And 

 so also the existence of albumen in abundance 

 round the embryo, or its absence, must be regarded 

 as a physiological character of the highest value: 

 because, in the former case, the embryo dematuisa 

 special external ju-ovision for its early nutriment, 

 as in oviparous animals; while, in the latter case, 

 the embryo is capable of developing by means of 

 the powers resident in itself, and unassisted, as in 

 viviparous animals. 



5. Next to this must be taken the structure of 

 the organs of fructification, by whose united action 

 the seed is engendered; for without some certain, 

 uniform, and invariable action on their part, the 

 race of a plant nuist become extinct. Thus we find 

 that the structure of the anthers, placentae, and 

 ovules, are more uniform than that of the parts sur- 

 rounding them, while their numbers are variable; 

 and the condition of the filament, which appears of 

 so little importance in aphysiological point of view, 

 is also inconstant. So also the texture, surface and 

 form of the jiericar)!, which actsasa mere covering 

 to the seeds, is not to be regarded in these inquiries, 

 and, in fact, dillcrs from genus to genus; as, for in- 

 stance, between Pyrus and Stranvsesia, or Rubus 

 and Spirfea, in the truly natural Rosaceous Order. 



6. On the other hand, the floral envelopes seem 

 to be unconnected with functions of a high oriler, 

 and to be designed rather for the decoration of 

 plants, or for the purpose of giving variety to the 

 aspect of the vegetable world; and, consequently, 

 their number, form, and condition, presence or ab- 

 sence, regularity or irregularity, are of low and 

 doubtful value, except for specific distinction. 

 There seems, indeed, reason to expect that every 

 Natural Order will, sooner or later, be found to 

 contain within itself all the variations above alluded 

 to. Even in the cases of regularity and irregularity 

 we already know this to be so; witness Veronica 



(5 



