Compositae

“ Thus Poales include Poaceæ and Cyperaceæ. Rosales include Rosaceæ and several families.
In other words, individual plants are grouped in species, species into genera, genera into families, and families into orders. These orders are themselves grouped into still larger divisions; there are, for instance, twelve orders comprising all the monocotyledons, and about twenty orders comprising all the dicotyledons. Once we have decided that any plant is a monocotyledon or a dicotyledon, our next step should be as to which order it belongs, then its family, its genus, and finally its species. ”

“ Here a complete plant grows from a fragment of a leaf stuck into the ground; and, in Begonia phyllomaniaca, complete plants grow even out of scales that fall from the leaves and the stem—a fact showing, like the fact which the polype furnishes, that the units everywhere present have for their type of aggregation the type of the organism they belong to; and reminding us of the universal fact that the units composing every germ, animal or vegetal, have a proclivity toward the parental type of aggregation. ”

“ Without recourse to the evidence afforded by the plants of past ages, we must always admit that our existing classification of the vegetable kingdom is an expression of real gaps which separate the several classes of plants from one another. On the other hand our recently acquired and more accurate knowledge of such genera as have been alluded to, has made us acquainted with types of plant structure which enable us to fill in some of the lacunae in our existing classification. ”

“ There is, at first sight, this broad difference between the descriptive language of Botany and of Comparative 350 Anatomy; that in the former science, we have comparatively few parts to describe, (calyx, corolla, stamen, pistil, pericarp, seed, &c.) : while each of these parts is susceptible of many forms, for describing which with precision many terms must be provided: in Comparative Anatomy, on the other hand, the skeletons of many animals are to be regarded as modifications of a common type, and the terms by which their parts are described are to mark this community of type. ”

“ The vegetable kingdom illustrates still more clearly the manner in which the aggregates are compounded. We have plants, like Caulerpa, which, while the form would lead us to expect a considerable degree of organization, consist in reality of a simple aggregation of homogeneous cells. In higher plants, the leaf forms a new order of organization, and constitutes the morphological individual or unit. In trees, the process of compounding has gone so far that, considered as individuals, they may reach the hundredth degree. ”

“ Variety comes in upon occasion. For, although a species may have no recognized varieties, a genus implies at least one species belonging to it; every genus is of some order, and every order of some class.
533. But these grades by no means exhaust the resources of classification, nor suffice for the elucidation of all the distinctions which botanists recognize. In the first place, a higher grade than that of class is needful for the most comprehensive of divisions, that of all plants into the two Series of Phanerogamous and Cryptogamous (6) ”

“ Now this uncertainty is of little moment, when we have them primarily distinguished and set apart from other plants by their Monoecious or Dioecious character; because the genera being few, and the Orders constructed widely as to number of Stamens, we find little difficulty in determining any genus, which would be by no means the case if we had them confounded with the mass of the system. Even the species of the same genus, as well as individuals of each species, differ among themselves. ”

“ If we compare the structure of the sporogonium of a moss or liverwort with the plant bearing the sexual organs, we find that its tissues are better differentiated, and that it is on the whole a more complex structure than the plant that bears it. ”

“ Fifty or sixty, and often more, bags of seeds are by no means uncommon for a single experiment, and in ordinary years the harvest of my garden is preserved in over a thousand separate lots.
Complying with these conditions, the origin of species may be seen as easily as any other phenomenon. It is only necessary to have a plant in a mutable condition. Not all species are in such a state at present, and therefore I have begun by ascertaining which were stable and which were not. ”

“ Very few of the genera of plants, or even of the families, can be pronounced with certainty to be Kinds. The great distinctions of Vascular and Cellular, Dicotyledonous or Exogenous and Monocotyledonous or Endogenous plants, are perhaps differences of kind; the lines of demarcation which divide those classes seem (though even on this I would not pronounce positively) to go through the whole nature of the plants. But the different species of a genus, or genera of a family, usually have in common only a limited number of characters. ”

“ When there is a general reduction in size throughout all the organs of a plant, or throughout all the nutritive organs, stem, leaves, &c., and the several portions participate in this diminished size, we have what are generally termed "dwarf varieties," dwarf in comparison, that is, with the ordinary condition of the plants; on the other hand, if the entire plant, or, at least, if the [Pg 414] whole of one set of organs be increased in size beyond the recognised average, we have large varieties, often qualified by such terms as macrophylla, longifolia, macrantha, &c. ”

“ The implication seems, therefore, to be that the living particles composing one of these fragments, have an innate tendency to arrange themselves into the shape of the organism to which they belong. We must infer that the active units composing a plant or animal of any species have an intrinsic aptitude to aggregate into the form of that species. It seems difficult to conceive that this can be so; but we see that it is so. Groups of units taken from an organism (providing they are of a certain bulk and not much differentiated into special structures) have this power of re-arranging themselves. ”

“ In respect to that progress which individual organisms display in the course of their evolution, this question has been answered by the Germans. The investigations of Wolff, Goethe, and Von Baer, have established the truth that the series of changes gone through during the development of a seed into a tree, or an ovum into an animal, constitute an advance from homogeneity of structure to heterogeneity of structure. In its primary stage, every germ consists of a substance that is uniform throughout, both in texture and chemical composition. ”

“ The obvious use of seeds is the distribution of the species by the formation of new individuals.
In the general outline which has been given of the elements, tissues, and organs of plants, they have been examined principally as existing in the higher groups, or those of more complex structure; and to enter further upon a description of these plants would involve the consideration of variations in the form and arrangement of the organs of which they are composed. ”

“ The great skill shown by the founders of the doctrine in the morphological consideration of the whole plant-form appears equally in the establishment of the rules, according to which the relations of position of the leaves of a side-shoot connect with those of the mother-axis, and which made it possible to represent the nature of inflorescences especially with extreme clearness by means of geometrical figures. ”

“ Proceeding to the detailed classification of Herbs, he divides them into Imperfect "which either do want or seem to want some of the more essential parts of Plants, viz. either Root, Stalk, or Seed," the Cryptogamia of Linnaeus; and Perfect "having all the essential parts belonging to a Plant." The Perfect Herbs are arranged in three main groups according to (1) their leaves, (2) their flowers, (3) their seed-vessel, each group being subdivided in various ways. ”

“ In plants we may pass from cases of slight alteration in the shape of a leaf, to cases where, instead of a flower with its calyx above the seed-vessel, there is produced a flower with its calyx below the seed-vessel; and while in one animal there arises a scarcely noticeable unlikeness in the length or colour of the hair, in another an organ is absent or a supernumerary organ appears. ”

“ A plant is said to propagate itself when it produces another specifically like itself; this is the idea in its broader acceptation. We see that here, as in Cesalpino, the idea of the species is connected with that of propagation. The second chapter, headed 'Plantae Partitio,' treats of the most important morphological relations in the external differentiation of plants ”

“ The first to recognize that morphological relations might exist between the organs of a plant, dissimilar as regards their function, was the poet, Goethe, whose observations, guided by his imaginative faculty, led him to declare that the calyx, corolla and other parts of a flower, the scales of a bulb, etc., were metamorphosed leaves, a principle generally accepted by botanists, and, indeed, extended to other parts of a plant, which are referred to certain common morphological forms, although they exercise different functions. ”

“ This figure as exhibiting a departure from the usual and regular form is not without its use, since it explains the cause of one of the greatest obstacles to the perfecting of the Linnean sexual system, depending as it does on a single set of organs, the tendency namely, of different flowers, even on the same stalk, to vary in the number of stamens and pistils, and thereby, to indicate very different places in the system for the plant to which they may belong. ”

“ There is almost infinite variety shown in the form and structure of the tissues and organs, this being particularly the case with the flowers. As already stated, the ovules, instead of being borne on open carpels, are enclosed in a cavity formed by a single closed carpel or several united carpels. To the organ so formed the name “pistil” is usually applied, and this is known as “simple” or “compound,” as it is composed of one or of two or more carpels. The leaves bearing the pollen spores are also much modified, and form the so-called “stamens.” ”

“ It seems plausible that the structure of a formation, if not as definite, is at least nearly as complex as that of an individual plant. Few botanists will insist that the refinement of tissues and tissue systems has been carried further than the differentiation of the plant warrants. ”

“ The history of the morphology and systematic botany of this period shows indeed, that the comparison of mature forms leads to the recognition of many and highly important morphological facts; but as long as matured organisms only are compared, the morphological consideration of them is always disturbed by the circumstance that the organs to be compared are already adapted to definite physiological functions, and thus their true morphological character is often entirely obscured ”

“ The type-species of every genus, the type-genus of every family, is then, one which possesses all the characters and properties of the genus in a marked and prominent manner. The type of the Rose family has alternate stipulate leaves, wants the albumen, has the ovules not erect, has the stigmata simple, and besides these features, which distinguish it from the exceptions or varieties of its class, it has the features which make it prominent in its class. ”

“ Such a difference of degree may be traced between the class of Vascular Plants and that of Cellular, which includes lichens, algæ, and other substances whose organization is simpler and more rudimentary than that of the higher order of vegetables, and which therefore approach nearer to mere inorganic nature. But when we rise much above this point, we do not find any sufficient difference in the degree in which different plants possess the properties of organization and life. The dicotyledons are of more complex structure, and somewhat more perfect organization, than the monocotyledons ”

“ While the polyphyletic origin of species is in a fair way to be decided by experiment, it receives support from several well-known phenomena. The striking similarity in the plant body of families taxonomically so distinct as the Cactaceae, Stapeliaceae, and Euphorbiaceae, or Cyperaceae and Juncaceae, indicates that a vegetation form may be polyphyletic. ”

“ Such differences they present in common with every higher plant; which, here in the shape of bark and there in the shape of cuticle, has an envelope inclosing it even up to its petals and stamens. In like manner among animals, there is always either a true skin or an outer coat analogous to one. Wherever aggregates of the first order have united into aggregates of the second and third orders—wherever they have become the morphological units of such higher aggregates—the outermost of them have grown unlike those lying within. ”

“ If we take a flower with this structure as the starting point, then the family developes partly into epigynous forms, partly into others which are so strongly reduced and exceptional that it is scarcely possible to refer them to the ordinary type. ”

“ After a longer or shorter time the mass of protoplasm contracts and gathers into little heaps, each of which develops into a structure that has no resemblance to any animal, but would be at once placed with plants. ”

“ But in spite of occasional exceptions this large group of polypetalous families do usually bear separate petals and sepals, and are among the most important of all the plant families. As they number over a hundred and contain thousands of species, all that can be done here is to mention a few typical or important ones. Just as in the apetalæ the families in this large group appear to show definite stages in development from simpler to more complex forms. But the steps are harder to trace and what appears simple characters in some plants are very complex in others. ”