ILLUSTRATIONS OF INDIAN BOTANY. 4°
in large quantity is essential to the admission of a family into his first group of polypetalous plants, but in all his subsequent ones this, the essence of his first, is sacrificed to the free or ad- herent ovary, or the parietal or axillary position of the placentas, and these again in turn give place to some other point of structure that might for the time happen to assume greater or less importance in the author's estimation. Hy thus assigning different values at different times to the same organs, Dr. Lindley has, I conceive, totally failed in the construction of a Natural System of Botany.
Exogens have, with a few rare exceptions, dicotyledonous seed, Endogens monocof yledon- ous ones, Acrogens are acotyledonous, hence the foundation of this system is essentially semi- nal being based on seminal structure. Why then, in the distribution of these primary classes into minor subdivisions or groups, have recourse to other organs, and these too of the most unstable kind, the presence or absence of one of the floral envelopes, or the union or freedom of its parts, when he could equally well, if not better, have supplied himself with secondary characters from the same organ that gave the primary — the seed ?
In the discussion of the Affinities of almost every order reference is made to the structure of the seed, whether albumenous or exalbumenous. Assuming that, this character possesses the high value assigned to it, and I believe it does, a much better distribution would have been into secondary groups depending, not upon the flowers being pnlypetalous, monopeJalom or in- complete, hut upon the seed being exalbumenous, albumenous or sub-albumenous. By this course (he high value originally attached to the structure of the seed would have been preserved and a uniform value assigned to its modifications. Characters taken from the flower would then, by having an equally uniform value assigned but of only secondary, in place of primary importance, have become much more useful in practice. Had this course been adopted I should at once have subscribed to the separation of these orders, but so long as our arrangement depend* for its primary divisions not on the albumenous or exalbumenous structure of the seed, but on the structure of the flower, 1 cannot subscribe to the logic of separating two orders closely associated by their floral arrangement because they differ in their seminal formation. For these reasons, which I have stated in detail because I think they involve an important principle in our attempts to construct a natural system of plants, I cannot adopt the reasoning of Dr. Lindley in separating these two orders. I have already under Ficoideae, indicated the place which I think the order ought to occupy on account of the structure of their fruit, without reference to that of the seed.
Geographical Distribution. Nearly the whole order are natives of America, those found in other countries are so generally naturalized plants that it is justly doubted whether there is one exotic to America.
Properties and Uses. On this subject nothing very important is known. The fruit of some of them are eatable, that of Cactus opunlia being highly esteemed all over the South of Europe, wheie it is known under the name of Indian Hig It is a fruit of easy digestion and on account of the acidulous sachaiii.e juice with which it abounds, is considered refreshing and very cooling. Some years ago the succulent stems of the same species were much employed in this counry as a vegetable and as such were largely supplied to the shipping frequenting the port, as a means of preventing scurvy among the sailors, for which, its property of long remaining fresh and green admirably qualifies it.. Of late years it has fallen into total disuse, perhaps from the facility of procuring more palatable ones.
It is narrated that the leaf-like stems of the common hedge Cactus when split through the middle and applied to the skin acts in a few hours as an effectual rubifacient, and is recommended as a remedy against gout, tooth-ache, &c. Dr. Cleghorn relates that in Minorca, he was in the habit of applying it to the chest in cases of Pluerisy, and with much relief to his patients. Similarly prepared it, is applied to painful corns for the purpose of taking them out by the roots. This it effects by keeping them bathed in moisture for several days which completely destroys them. A piece of adhesive plaster kept over a corn for several days produces the same effect, by retaining the perspiration on the part. Directly, this order contributes but little to either the necessaries or luxuries of life, but indirectly, it does so extensively, by supply-
