BOOK REVIEWS

Flowering Plant Families of the World

By V.H. Heywood, R.K. Brummitt, A. Culham, and O. Seberg
Kew Publishing, Kew
Hardback, 424 pages, 250 × 320mm, Canada, 2007
ISBN 978-1-84246-165-5
NZ$110.00

Reviewed by Peter Heenan

This book is a valuable addition to the library of anyone interested in flowering plants, whether they be a gardener, student, amateur botanist, or with a stronger scientific background. It contains a wealth of information on distribution, morphology and anatomy, habitat, classification, important genera, economic uses, and key literature. This book is the successor to the well-known Flowering plants of the world (Heywood, 1978), an essential botanical reference for nearly three decades. Although both books appear alike in that they have a similar layout and use many of the same illustrations, the majority of the text in Flowering plant families of the world has been totally rewritten.

This book has an excellent layout that includes a brief introductory section, an overview of the classification used, and an excellent glossary. The main part of the text comprises the family treatments and these are presented in alphabetical order for each of the two major groups of flowering plants, the dicotyledons and monocotyledons. Each family entry is divided into four sections: distribution, description, classification, and economic uses. In addition, many of the larger or better known families have an introductory paragraph. The descriptions contain, by necessity, a great deal of invaluable technical information that may be difficult to read for many, but the sections on distribution, classification, and economic uses are clearly written, easily read, and contain a wealth of information.

A major difference from the Flowering plants of the world (Heywood, 1978) is that this new book includes details of 506 families, whereas its predecessor had only 306. This
increase in family number is primarily due to the new book following a system of classification proposed by the Angiosperm Phylogeny Group (APG II, 2003) as modified by Soltis et al. (2005). In comparison, the 1978 Flowering plants of the world was based on the Stebbins system of family classification. Although this new book is based on the APG II system that accepted 457 families, it includes another 49 families considered by the authors to be worthy of recognition.

The authors claim in the introductory pages that they have “refrained from offering a new system of classification or a further modification of APG II” (p. 8) and “it is not our intention to present a new system of classification but to provide a synthesis of the latest information” (p. 10). However, by formally treating 506 families, accepting an additional 49 families to the APG II, and presenting arguments for the families they accept or reject, they have surely implied an alternative system. The classification adopted in this book is unique and, despite the authors’ protestations, will almost certainly come to be regarded as an alternative system of family classification.

Since the publication of Flowering plants of the world in 1978, knowledge of the relationships of flowering plants has changed considerably as new information has come to hand on anatomy, morphology, and in particular phylogenetic relationships based on DNA sequence data. A real strength of this book is that it incorporates much of this new information, but in doing so it also compares traditional and recent views on relationships. If the authors disagree with an alternative classification to their own they usually provide an overview of the other classification and their reasons for not following it. A good example of this is provided in the discussion of the Scrophulariaceae, although the introductory comments to this family read more like a medical condition than scientific debate: “A family in the throes of dismemberment and reassimilation, with consequent major disruption of internal parts” (p. 300). This notion is further reflected in the discussion for the Scrophulariaceae where the debate considers the cladistics school of thought in accepting only monophyletic families or the alternative and “only logical solution” of accepting paraphyletic taxa. As noted in the book’s introduction (p. 9), the use of taxonomic “rank is a matter for taxonomic decision and preference and ultimately consensus”.

The distribution maps for each family are very small but are appropriate for the type of information they convey. However, in regard to New Zealand plants several errors were
detected. These include, for example, New Zealand not having shading to indicate the Nyctaginaceae (Pisonia brunonia) being indigenous. On the other hand, New Zealand
is erroneously shaded as having indigenous species of Celastraceae, Lythraceae, Najadaceae, Smilacaceae (Rhipogonum is now in Rhipogonaceae – note the spelling with an ‘h’), and Vitaceae. Shading of New Zealand also occurs for the monocotyledons Asphodelaceae and Colchicaceae and this raises another issue. Due to recent changes in the circumscription of families, particularly in the monocotyledons, it is often difficult to know what genera are currently included in a particular family; the book does not include a comprehensive list of genera and their family placements. In the case of Colchicaceae the New Zealand species is probably Iphigenia novaezelandiae. However, for the reader interested in New Zealand plants there is no indication of what indigenous genera may now be included in the Asphodelaceae and Colchicaceae, or are these perhaps errors. In contrast, some of the maps are very accurate. For example, the Lauraceae map includes the upper South Island being shaded, which represents the distribution of Beilschmiedia tawa.

I detected only one major error, this being the rather unfortunate omission of the Stackhousiaceae, including the New Zealand species Stackhousia minima. On pages 11 and 93 the Stackhousiaceae is indicated as being an accepted family, this being in contrast to its recent placement as a subfamily of Celastraceae. However, in the index and the main body of the text the Stackhousiaceae entries are missing.

It is apparent when reading the book that a considerable number of families have only 1–3 genera and/or very few species, and that some of these account for a number of the families that are additional to those recognised by APG II. An interesting family placement of this type and of relevance to a New Zealand reader includes Samolus being placed in the monogeneric Samolaceae, whereas in APG II (2003) it was in the Theophrastaceae and prior to that in the Primulaceae (Webb et al., 1988). Other New Zealand genera that are the only genus in their family include Coriaria, Corynocarpus, Donatia, Griselinia, Pennantia, Quintinia, Rhipogonum, Tetrachondra, and Xeronema. There are a number of other New Zealand genera that have also been assigned to very small families. Included among these are the enigmatic Hectorellaceae, comprising the New Zealand endemic Hectorella and the Kerguelen Island endemic Lyallia. The relationships of these two genera have been problematic for many years and they are included in the Hectorellaceae by Flowering plant families of the world. However, highlighting the speed with which new information can come to hand, a very recent phylogenetic study using three gene regions has shown they belong with the Portulacaceae and they are now included there as the subfamily Hectorelleae (Applequist et al., 2006). This book is very readable and highly informative, containing an absolute wealth of up-to-date facts and figures on the flowering plants of the world. It would make a valuable addition to the library of any plant enthusiast.

References
APG II (2003). An update of the Angiosperm Phylogeny Group classification for orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141: 399–443.

Applequist, W.L.; Wagner, W.L.; Zimmer, E.A.; Nepokroeff, M. (2006). Molecular evidence resolving the systematic position of Hectorella (Portulacaceae). Systematic Botany 31: 310–319.

Heywood, V.H. (1978). Flowering plants of the world. Oxford, Oxford University Press.

Soltis, D.E.; Soltis, P.S.; Endress, P.K.; Chase, M.W. (2005). Phylogeny and evolution of Angiosperms. Sunderland, Sinauer.

Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. (1988). Flora of New Zealand. Vol. IV. Christchurch, Botany Division, DSIR.

Reproduced with permission from the New Zealand Journal of Botany, 2008, Vol. 46:103–104.

A separate review of this book was published by Rhys Gardner in the NZ Botanical Society Newsletter 91, March 2008: 21–22.