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RECENT LITERATURE.

DARWIN'S DIFFERENT FORMS OF FLOWERS ON PLANTS OF THE SAME SPECIES^1.—All botanists may not become Darwins, but if a perusal of this and the other works of their talented author, should induce any of the present collectors of local floras, and describers of dried plants, to at least devote a moiety of their leisure to observing flowers, their daily conduct of life, how they grow and reproduce their kind, their relation to one another, to insects and to the world at large; observations, however, in many cases requiring care and patience, as well as some genius, then would in time be reared a crop of botanists, who would bridge the chasm now yawning between the ordinary herbalist—no farther advanced now, perhaps, than in the days of Gerarde—and the author of this book and its predecessors. This work, however, interesting as it is, was not written for the public, but for the few who have, since 1862, read the Journal of the Linnean Society, which contains the papers forming the body of this book, which are here republished in a connected and corrected form, together with some new matter, and is now in such an attractive form that few who have read Mr. Darwin's former writings will neglect the present work.

Premising that, in the words of the author, cleistogamic flowers are fertile, minute, completely closed, with the petals rudimentary, often with some of the anthers abortive, and the remaining ones together with the stigmas much reduced in size; that these flowers grow on the same plant with perfect and fully expanded flowers—we will now let the author give the results of his studies:

"I will now sum up very briefly the chief conclusions which seem, to follow from the observations given in this volume. Cleistogamic flowers afford, as just stated, an abundant supply of seeds with little expenditure; and we can hardly doubt that they have had their structure modified and degraded for this special purpose; perfect flowers being still almost always produced so as to allow of occasional cross-fertilization. Hermaphrodite plants have often been rendered monœcious, diœcious, or polygamous; but as the separation of the sexes would have been injurious, had not pollen been already transported habitually by insects or by the wind from flower to flower, we may assume that the process of separation did not commence and was not completed for the sake of the advantages to be gained from cross-fertilization. The sole motive for the separation of the sexes which occurs to me, is that the production of a great number of seeds might become superfluous to a plant under changed conditions of life; and it might then be highly beneficial to it that the same flower or the same individual should not have its vital powers taxed, under the struggle for life

¹ The Different forms of Flowers on Plants of the same Species. By CHARLES DARWIN, M. A., F. R. S., with illustrations. New york, D. Appleton & Co., 1877, 12mo., pp. 352.

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to which all organisms are subjected, by producing both pollen and seeds. With respect to the plants belonging to the gyno-di-œcious sub-class, or those which co-exist as hermaphrodites and females, it has been proved that they yield a much larger supply of seed than they would have done if they had all remained hermaphrodites; and we may feel sure from the large number of seeds produced by many plants that such production is often necessary or advantageous. It is therefore probable that the two forms in this sub-class have been separated or developed for this special end.

Varius hermaphrodite plants have become heterostyled, and now exist under two or three forms; and we may confidently believe that this has been effected in order that cross-fertilization should be assured. For the full and legitimate fertilization of these plants pollen from the one form must be applied to the stigma of another. If the sexual elements belonging to the same form are united the union is an illegitimate one and more or less sterile. With dimorphic species two illegitimate unions, and with trimorphic species twelve are possible. There is reason to believe that the sterility of these unions has not been specially acquired, but follows as an incidental result from the sexual elements of the two or three forms having been adapted to act on one another in a particular manner, so that any other kind of union is inefficient, like that between distinct species. Another and still more remarkable incidental result is that the seedlings from an illegitimate union are often dwarfed and more or less or completely barren, like hybrids from the union of two widely distinct species."

BREHM'S ANIMAL LIFE.¹—We have already (Vol. xi. p. 557) in general terms called attention to the elaborate and useful work of which the present volume forms a part. Prof. Taschenberg, the author or this volume, is well known for his studies on the lower Hymenoptera and his work on economic entomology. He brings to the task ripe scholarship, a pleasant style, and is aided by an artist whose success greatly enhances the value of the work. In a few introductory pages, Prof. Taschenberg treats of the anatomy, physiology, and transformations of insects, and then enters at once upon a very general description of the more interesting forms of the families of insects, beginning with the beetles and ending with the myriopods, spiders and mites. The Linguatulidœ, and Pantopoda (Pycnogonidæ) are included, and the Tardigrades are briefly noticed.

The work is well worth the cost to one even who cannot read German with facility, from the graphic, full-page illustrations, and the cuts which abound in the text. The picture of the dead and probably stinking mole hanging by its snare, and overrun with a

¹ Brehm's Thierleben. Band 9. Die Insekten, Tausenfüssler und Spinner. Von DR. E. L. TASCHENBERG. Mit 227 Abbildungen im Text und 21 Tafeln, von Emil Schmidt. Leipzig, 1877. New York, B. Westerman & Co. New York. 8vo. pp. 711, xx. $5.00.