“5. That the umbellules were on stalks both longer and thicker than those of single flowers.”
[Concerning the foregoing argument at large an expert writes:—“The abnormalities you describe certainly show that an axis may arise abnormally in the place of a normal leaf-structure, and every modern botanist would be in agreement with you in your criticism of the older form of the doctrine of axillary buds. I think we are largely emancipated from the dextrous juggling with the arrangements and relations of organs which used to pass current as morphology.
“You have quoted sufficient evidence in the text ([§ 190]) to establish the conclusion that no sharp line can be drawn between axes and leaf-structure; and a very great deal more could be added in the same sense. Petioles for instance, exist which the most highly trained histological observer could not distinguish from stems.
“But I must demur to the suggestion that the replacement of one by the other is primarily a question of nutrition. We are as ignorant as ever of the proximate cause of the production of a leaf or a shoot at a certain spot in meristematic tissue.”
To this last remark I had at first made only the reply that the plants exhibiting the abnormalities were in all cases excessively luxuriant in their growths; but to this I am now able to add a more definite reply. The expert from whom I have just quoted, had read this appendix before there had been made to it the above addition describing the flower from Dieppe; and I was not myself aware, until I came to read over this addition, what clear evidence it contains that extra nutrition was the cause of these transformations of foliar structures into axial structures; but the above paragraphs 1, 2, 3, 4, 5, contain different evidences conspiring to prove this.]
APPENDIX B.
A CRITICISM ON PROF. OWEN’S THEORY OF THE VERTEBRATE SKELETON.
[From the British & Foreign Medico-Chirurgical Review for Oct., 1858.]
I. On the Archetype and Homologies of the Vertebrate Skeleton. By Richard Owen, F.R.S.—London, 1848. pp. 172.