Evolution and Speciation of Island Plants Stuessy, Tod F., and Mikio Ono, eds. 1998. ISBN 0521-4963-5 (cloth US$80.00), 358 pp. Cambridge University Press, 40 West 20th St., New York NY 10011-4211.

Although islands in the sea account for only 3% of Earth's land area, and individual islands have impoverished communities, the pooled number of species on islands is great. For example, around 15% of all known species of birds and plants occur on islands (Hanski, Nature, I Apr 1999, p. 387), and islands are considered evolutionary laboratories where adaptive radiations are taking place over smaller time and space scales than elsewhere. The immense and diverse primary literature has spurred several recent books that have tried to synthesize general insights from island studies (e.g., Wagner and Funk, 1995). If one is looking for a recent comprehensive single-author treatment of island ecology, Robert Whittaker's (1998) "Island Biogeography: Ecology, Evolution and Conservation" (an Oxford University Press paperback sells for $29.95) would be an excellent choice. However, as pointed out by llkka Hanski (loc. cit.) in his review of "Island Biogeography," a book that covers the full range of topics from geography and geology of islands, to speciation on islands, population assembly, to the application of island theory to conservation, may be comprehensive, but offer no surprises. It may describe' complexity, but not explain any of it.

The book under review here brings together work on the plant biology of oceanic island systems, including the Hawaiian Islands, Canary Islands, Bonin Islands (Japan), and the Juan Fernandez Islands (Chile), and it contains several surprises. It is the result of a symposium held during the XV International Botanical Congress in Yokohama, Japan. In addition to the papers from the symposium itself, which focused on Pacific archipelagos, several additional manuscripts were solicited to provide a "more comprehensive review of the status of studies of plant evolution on oceanic islands." There are 13 chapters by 18 contributors, of whom six are from Japan, one from Korea, seven from the US or Canada, and three from Chile, and the chapters are grouped by island system. A final part, entitled "General evolutionary patterns and processes on oceanic islands," contains a review of secondary compounds in island plants (Bruce Bohm), a chapter on chromosomal stasis during speciation in island angiosperms, and a chapter in which the editors summarize the current status of knowledge on plants of island archipelagoes and suggest what are termed research protocols. (The latter unsurprisingly involve continued basic floristic inventories using consistent species concepts, explicit evolutionary and phylogenetic hypotheses, the gathering of more geological data, and rigorous biogeographic analyses.)

Tod Stuessy and his collaborators' long-standing interest in chromosome evolution is evident in this volume, which starts out with a review by Gerald Carr of chromosome evolution in Hawaiian angiosperms and the main part of which ends with Stuessy and Crawford's attempt at explaining the marked discrepancy between morphological divergence and near absence of chromosomal change seen in many island groups. Chapter 2 is a summary of work on the Hawaiian silverswords (Bruce Baldwin), chapter 3 (Stuessy, Crawford, Marticorena and Silva) deals with isolating mechanism in the endemic angiosperms of the Juan Fernandez archipelago (spatial isolation between islands accounts for 70% of closely related species pairs), and chapter 4 (Crawford, Sang, Stuessy, Kim, and Silva) contrasts two genera of Asteraceae in terms of their biology, speciation, and estimated time of residence on Juan Fernandez. While Whittaker in his above mentioned "Island Biogeography" takes the view that MacArthur and Wilson-type island biogeographic theory (MacArthur and Wilson, 1967) is essentially dead - a view not shared by reviewer Hanski - "Evolution and Speciation of Island Plants" contains a chapter (5; Stuessy, Crawford, Marticorena, and Rodriguez) in which an equilibrium model is developed that predicts numbers of species on Masafuera (one of the Juan Fernandez Islands). The model estimates 70.5 species on Masafuera whereas there really are 64. The next four chapters deal with the genetic diversity of endemics on Bonin (Ito, Soekima, and Ono), the evolution of cryptic dioecy in Callicarpa on Bonin (Kawakubo), conservation of endemic vascular plants on Bonin (Ono), and chromosomal evolution of endemic species on Ullung Island compared to their presumed ancestors from Korea and Japan (Sun and Stuessy). The section on Asian oceanic islands ends with a beautifully illustrated summary of their work on the South Pacific mangrove genus Crossostylis by Setoguchi, Ohba, and Tobe.

"Evolution and Speciation of Island Plants" is beautifully produced and very carefully edited, and while it covers a limited set of plant biological questions and oceanic islands, the editors and authors are serious about trying to explain, rather than describe, plant speciation and evolution on "their" islands.

- Susanne Renner, Biology, University of Missouri, St. Louis

Literature cited

MacArthur, R. H., and E. O. Wilson. 1967. The Theory of Island Biogeography. Princeton Univ. Press.
Wagner, W. L., and V. A. Funk (eds.). 1995. Hawaiian Biogeography: Evolution on a Hot Spot Archipelago. Smithsonian Institution Press.
Whittaker, R. J. 1998. Island Biogeography: Ecology, Evolution and Conservation. Oxford Univ.