Angiosperm Origins: Morphological and Ecological Aspects. Krassilov, V. A., 1997. ISBN 954642-016-6 (paper US $38.50). 270 pp., 59 figs., 47 plates. Pensoft Publishers, Sofia-Moscow, Acad. G. Bonchev Street, Bl. 6, 1113 Sofia, Bulgaria.- Few issues in the history of evolutionary botany can have attracted as much attention as the origin of angiosperms. There has been substantial progress with some aspects of this cluster of research problems (see Crane et al., 1994, Nature 374: 27-33 for a review), but it is also true that some of the central questions, including the precise homologies of the angiosperm carpei, seconci integument and stamen to the reproductive structures of other seed plants, have continued to elude convincing solution. The apparent lack of progress on these issues is frustrating - but not unusual: similar problems confound clear establishment of homologies among structures that characterize the major lineages of Metazoa. However, the positive side of such an impasse in evolutionary biology is that it is fertile ground for new ideas, which at their best are bold, and stimulate or provoke us to look at old problems in new ways. Valentin Krassilov has never shied away from bold ideas, and this book follows in the same vein as some of his earlier work. The challenge to the reader is to decide whether his perspective promises a way around the roadblocks in our current thinking, or are simply more blind alleys that are unlikely to result in progress.
The book begins with brief introductory remarks and ends with two pages of conclusions. In between, it is divided into five sections: Making of the Type, Prehistory, Early History, Environments and Phylogeny. In Making of the Type, Krassilov deals with philosophical and practical issues governing the recognition of taxa, while in the next two sections he introduces some of the major lineages of seed plants and angiosperms and attempts to identify the links between them. In the section on Environments he develops the notion that "angiosperm origins were an integral part of Mesozoic plant community evolution." Finally, in the section on phylogeny he attempts to explain the origin of characteristic angiosperm features by reference to structures in putative "proangiosperm" precursors. The book is produced in an attractive, easy to use, and excellent format by Pensoft Publishers, who deserve great credit for the quality of the presentation.
For a paleobotanist, Krassilov's world view, like that of the late Norman Hughes, is inspiring because it argues for the significant role of paleobotanical data in helping to resolve some of the intractable questions in studies of angiosperm evolution. However, also like Hughes, Krassilov casually dismisses data from extant plants, and is frustrating in continuing to imply, or directly argue for, angiosperm polyphyly from precursors as diverse as Irania (Dirhopalostachyaceae), Gnetales, Caytonia-and Leptostrobus. His suggested phylogenetic relationships link: Irania to platanoids, rosids and Hamamelidales; Gnetales with Juglandales/Myricales on the one hand and Piperales, Laurales, Nymphaeales on the other; Baisia with the monocots; Leptostrobus with the Magnoliales; and Caytonia with ranunculids, Paeoniales, and dilleniids. Broad, and often manifestly superficial, similarities between extant plants and often poorly known fossils are the basis for these ideas.
Krassilov's presentation of intriguing fossil material, both from his work and from the work of colleagues in the Russian Far East, highlights the wealth of fascinating and potentially relevant Cretaceous plants that remain to be described, and one of the real highlights of this book are the 48 good quality plates that illustrate some of this material. Excellent plate legends further contribute to making this section of the book an important addition to the paleobotanical literature. Unfortunately, on the negative side the sometimes over enthusiastic interpretation of the fossil material detracts from the fact that among the plates are a fascinating suite of extinct plants about which we currently know much too little. If we knew them better they might well help us solve some of the key questions to which Krassilov draws attention. This will require painstaking and careful paleobotanical work, and - most probably - fossil material that is much-better preserved.
Krassilov's classification of extant angiosperms and the assignment of fossils to these groups is also unashamedly idiosyncratic. For example, having been involved in the original descriptions of some of the fossils he discusses, I am just bewildered as to why Archaeanthus is affiliated with the ranunculids, and why Lesqueria is affiliated with the hamamelids. It is also unfortunate that while Krassilov's coverage of the paleobotanical data is reasonably up-to-date there is little attempt to try to integrate the exciting and rapidly accumuiating new information from molecular systematics on large-scale patterns of relationships among major angiosperm groups.
Overall, then, this book joins a particular genre of publications on angiosperm origins. Like the writings of Hughes, Meeuse, Melville and others it is at once both inspiring and frustrating. It presents fascinating and important data (mainly in the form of the plates) but in a theoretical framework that many will find strange, perhaps annoying, but most importantly, unhelpful. Many of the ideas are bold but they raise more questions than theyanswer. Thisisnotthebooktogivetoastudentwho wants a balanced overview of current work in this area. It is, however, a significant addition to the literature for the serious specialist who can filter out the distractions and appreciate its true value. - Peter R. Crane, The Field Museum, Chicago