Commelinidae

Abstract: s and mission will provide readers with a glimpse of some of the topics that are currently under investigation in Africa. This author’s latest fieldwork efforts in Africa, between October and December 2003, lead her to prize the reports contained in this volume. The Convention for Biological Diversity has focused new attention on indigenous biodiversity in low-income countries. It empowers heads of national Gene Banks to issue stern concerns about benefit sharing and access to genetic resources. While most countries have not yet codified their regulations about access to genetic resources, anyone interested in studying plants is now subject to intense scrutiny and may be denied permission outright. It seems unfortunate that previous collaborations that were easy are prohibited, and very obscure taxa that were up to this time ignored by scientists, are stalled by overly zealous petty bureaucrats. It makes research reported in this book less achievable. Other seasoned scientists understand that this viewpoint is too narrow and the result is a loss to science as well as to their nation, but have no power to influence the new administrators. It seems that it will take half a decade or more to sort this out. Meanwhile, research subjects that are already so little investigated, have low or no economic impact, and have been thoroughly neglected continue unstudied. It is shameful to waste these opportunities while permanent loss in biodiversity of wild species, crop landraces and habitats rush ahead, unabated. DOROTHEA BEDIGIAN WASHINGTON UNIVERSITY, ST. LOUIS AND MISSOURI BOTANICAL GARDEN Tarweeds & Silverswords, Evolution of the Madiinae (Asteraceae). Sherwin Carlquist, Bruce G. Baldwin, and Gerald D. Carr (eds.). 2003. Missouri Botanical Garden Press, PO Box 299, St. Louis, MO 63166-0299. xiv 1 294 pp. (paperback). $29.95. ISBN 1-930723-20-2. The Hawaiian silversword-complex of three genera (Argyroxiphium, Dubautia, and Wilkesia: Asteraceae) represents one of the most spectacular cases of adaptive radiation in island systems. It is probably cited as a case study second only to Darwin’s finches as an example of speciation and evolution in textbooks. This eleven chapter book (8 authored by the editors) is a multi-author effort presenting all of the most up to date results of studies on the subtribe Madiinae in the sunflower family. Having all these research projects in one volume is ideal for the scientist wishing to understand the subtribe. It also will be useful as an example to students exemplifying different experimental approaches that may be used to study the evolutionary patterns of plant lineages. In the first two chapters of this book, co-editor Baldwin summarizes the natural history and morphological character variation that occurs in the continental tarweeds and the Hawaiian silverswords. These chapters describe the morphological and ecological diversity in the group which range from sea-level to alpine habitats, inhabit arid regions and one of the wettest localities in the world, are annuals and perennials, and range from herbaceous species to shrubs, large trees, vines, and monocarpic rosettes. He also discusses the variation in floral morphology and additional characters in detail. The following two chapters, by co-editor Carr, thoroughly elucidate the chromosome evolution and rearrangements that take place among the species 122 [VOL. 58 ECONOMIC BOTANY of the alliance. This led to the discovery that hybridization played a significant role in the radiation of the lineage and to artificial hybridization experiments that have even produced a tri-generic hybrid. These studies helped explain the origins of the Hawaiian species. The next three chapters are authored by the third editor, Sherwin Carlquist. These chapters focus on the anatomy of the trichomes and glandular structures (the exudate of these give the California tarweeds their common name), leaves (which range from reticulate to longitudinally oriented appearing almost parallel), and wood (which shows remarkable changes that relate to the group’s adaptation to the diverse habitats and habits). The ensuing three chapters are not by the co-editors. Chapter 8, by Bohm and Yang, surveys the secondary metabolites that vary among the lineages of the subtribe and discuss systematics of the group based on flavonoid loss and gains throughout the evolutionary history of the lineage. The subsequent chapter delves into an investigation of floral regulatory genes and the correlation of these genes to the wide phenotypic diversity in the group which was discussed by Baldwin in Chapter 2. Once again the researchers, Purugganan, Remington, and Robichaux, show the difficulty applying techniques perfected in model systems and to natural systems when the group under investigation has undergone polyploidy and chromosomal rearrangements as is the case in the silversword-complex. Coauthors Friar and Robichaux summarize the conservation concerns facing some of the rare members of the Hawaiian group and the problems of implementing preservation strategies. They use a genetic fingerprinting approach to examine genetic diversity in the remaining individuals of the Mauna Kea silversword. The last chapter by Baldwin ties the preceding ten chapters together nicely. He examines the character evolution, ecology, and biogeography of the Madiinae in a phylogenetic context. Two appendices follow that clarify the taxonomy of the group and they include a list of all taxa and synonymy and a nomenclator that reflects the most recent treatments of the tarweeds and

Abstract: Summary The angiosperms are treated as a division Magnoliophyta, with two classes, the Magnoliatae (dicotyledons) and Liliatae (monocotyledons). Takhtajan's six subclasses of Magnoliatae are accepted with only minor alteration. These are the Magnoliidae, Hamamelidae, Caryophyllidae, Dilleniidae, Rosidae, and Asteridae. His four subclasses of Liliatae - the Alismatidae, Arecidae, Commelinidae, and Liliidae - are also accepted, but with a major transfer of the Zingiberales, Bromeliales, Juncales, and Cyperaceae from the Liliidae to the Commelinidae. The aquatic ancestry of the Liliatae has had a profound influence on the subsequent evolutionary history of the group. Loss of cambium, loss of vessels (except for some vestiges in the root), and reduction of the leaf to a phyllode are all probably associated with the ancestral aquatic habitat. The fact that habital differences are often taxonomically more important among the monocots than they usually are among the dicots reflects the evolutionary difficulties under which monocots labor. The single cotyledon of monocots is considered to have arisen by lateral fusion of two, followed by reduction of one of the lobes, and the sheath-blade structure of the leaves is considered to reflect the cotyledonary structure.