Seite - 227 - in The Origin of Species

THEORY OF NATURAL SELECTIOM 227 following cases : the genus Zanthoxylon belongs to a division of the Rutacese with a single ovary, but in some species flowers may be found on the same plant, and even in the same panicle, with either one or two ovaries. In Helian- themum the capsule has been described as unilocular or 3-locular; and in H. mutabile, "Une lame, plus on mains large, s'etend entre le pericarpe et le placenta." In the flowers of Saponaria officinalis, Dr. Masters has observed instances of both marginal and free central placentation. Lastly, St. Hilaire found towards the southern extreme of the range of Gomphia olea^formis two forms which he did not at first doubt were distinct species, but he subsequently saw them growing on the same bush; and he then adds, "Voila done dans un meme individu des loges et un style qui se rattachent tantot a un axe verticale et tantot a un gynobase." We thus see that with plants many morphological changes may be attributed to the laws of growth and the inter-action of parts, independently of natural selection. But with re- spect to Nageli's doctrine of an innate tendency towards perfection or progressive development, can it be said in the case of these strongly pronounced variations, that the plants have been caught in the act of progressing towards a higher state of development ? On the contrary, I should infer from the mere fact of the parts in question differing or varying greatly on the same plant, that such modifications were of extremely small importance to the plants themselves, of whatever importance theymay generally be to us for our clas- sifications. The acquisition ofa useless part canhardly be said to raise an organism in the natural scale ; and in the case of the imperfect, closed flowers above described, if any new principle has to be invoked, it must be one of retrogression rather than of progression; and so it must be with many parasitic and degraded animals. We are ignorant of the exciting cause of the above specified modifications; but if the unknown cause were to act almost uniformly for a length of time, we may infer that the result would be almost uniform ; and in this case all the individuals of the species would be modified in the same manner. From the fact of the above characters being unimportant