[page] 534

Mr. Darwin's book on "The Forms of Flowers"15 is described by the author as a reprint of a series of papers communicated to the Linnean Society, connected and corrected, together with new matter, and an abstract of the researches of others. Following the grouping of flowers adopted by Linnaeus into hermaphrodite, monæcious, diæcious, and polygamous species, each of these types is expounded at length. The hermaphrodite class contains, among other less important groups, the heterostyled dimorphic, and trimorphic species, and cleistogamic plants, to which the volume is chiefly devoted. It is "shown that hetero styled plants are adapted for reciprocal fertilisation; so that two or three forms, though all are hermaphrodites, are related to one another almost like the males and females of ordinary unisexual animals." The cleistogamic plants are adapted for self-fertilisation, and have two kinds of flowers, one of which is fully expanded and perfect, the other minute and closed, with their elements more or less aborted or rudimentary, yet perfectly fertile. As in some other of Mr. Darwin's books, the details and technical information are printed in smaller type. The book is well arranged, excellent in its clearness, well illustrated, and will take rank as one of the most perfect of the mono graphs with which its author has enriched biological science.

15 "The Different Forms of Flowers on Plants of the Same Species." By Charles Darwin, M.A., F.R.S. With Illustrations. London: John Murray. 1877.