90 NEW PUBLICATIONS.
of the stem of arboroseent Ferns, Professor Bentley, <ns seems to be generally the case with English writers, lias missed the significance of the openings in the vascular cylinder, which are not at all for the purpose of the conimunication of the cortical and medullary parenchyma, but are in reality the organic bases of the leaves. This was pointed out by Mohl, and has also been independently ascertained by ^Ir. Carruthers. It nnist inevitably soon be impossible to study apart the existing and extinct types of organized structures; it would be a philosophical proceeding to antici- ))ate what cannot be long delayed.
The pages of this ' ]\Ianual ' are profusely supplied with beautiful illus- trations, in a large number of cases, it is true, common to this and other English text-books, and acknowledging a common parentage in the ' Atlas ' of Le Maout. A perusal of the part dtvvoted to organography is much facilitated by their aid. Perhaps more might be done, as witii the fruits mentioned above, in omitting detail and describing structures in more general language. Under the head, for example, of "aerial modifi- cations of stems," we have the runner, offnet, slolou, sucker, and rhizome, from which the sobules is sepnrated as a " subterranean modification;" of these the runner and offset on the one hand, and the sucker, rhizome, and soboles on the other, have nothing essential that distinguishes them, while the stolon, as defined here, is more a habit than a structure; yet so purely is the whole t-hiiig a matter of theory, that further on, under the head of roots, we have a whole page occupied, somewhat apologetically, it is true, with the rhizomes of Scabiosa succisa and Poli///ouuni Bislorla.
A special excellence belongs to the systematic portion, especially in the econouiic details, — a hunt through these shows how very carefully this part of the subject has been worked up, indeed, for purposes of re- ference, it will be found almost indispensable in these malters to possess the ' Manual.' The sequence of the Orders is mainly Candollean, with apparently nothing borrowed from the labours of Hooker and Bentham. Something might have been done to indicate by difference of type the more important Orders, and seven pages devoted to an exposition of Linnsean classification are utterly wasted.
The physiology has been revised by Dr. Trimen, but a space so limited as eighty pages must have made it difficult to do more than scanty justice to this important but, in this country, little-studied side of botany. Ee- cent researches have, however, by no means been overlooked, and we have brief notices of the histological nomenclature of Dr. Beale, Mr. Spencer's views on the movements of sap, clind)ing plants as stiulied by Darwin, etc. It is satisfactory also to notice that points stated in earlier pages somewhat too absolutely, are here often modified. This is the case with the account given of germination (p. 789). As a matter of fact, though contrary to what is said in books, it is almost impossible to lay down any criterion for distinguishing the germination of Monocotyledons and Dicoty- ledons which does not in some case or other break down. The statements nuide in the former edition as to the prolonged vitality of seeds have beeu altered; the case of Nelumbium, from fSir Hans Sloane's herbarium, is probably one of the best authenticated, but it wdl still tax the credulity of many readers to see that it is thought possible that seeds deposited when the valley of the Tweed was a lake, would gernuuate now. To some persons the existence of batrachians, contemporary with a carboni- ferous flora, yet still living in coal mines, is not incredible; in fact, a
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