The Flowering of Australia’s Rainforests: A Plant and Pollination Miscellany
By Geoff Williams and Paul Adam
CSIRO Publishing, Melbourne. 2010
“The essential purpose” of this book, the authors state in their preface, is “to project some of the specialist knowledge that is available on the pollination ecology of Australian rainforest ecosystems into a more popular and accessible arena.” (p. xi). However, on reading this book it soon became apparent that the “popular arena” the authors had in mind was not the airport bookshop or your local Dymocks store. Take, for example, the introduction to plant breeding systems:
“Essentially there are three main categories of breeding systems in plants (though overall angiosperm pollination strategies comprise a continuum). These are represented by obligate out-crossing species (dioecious and self-incompatible hermaphrodite species), facultative out-crossers (monoecious, gynomonoecious, protandrous and protogynous species) including some self-compatible hermaphrodites, and facultative inbreeders (self compatible and apomictic plants). In the third group are some apomicts (discussed below), in which inbreeding is obligatory.” (p. 61)
Given the lack of a glossary, this book will be very heavy going for any but the most determined natural history enthusiast lacking a specialised education in biology and probably also for biologists who have not learnt much about the biology of whole organisms. So this book is definitely targeted at fellow scientists, and especially evolutionary ecologists, rather than “ordinary people”. This is a worthy aim, as few reviews of the pollination biology of Australian plants have been published and none of these is monographic in scale, comprehensive in scope or focused on the rainforest biome. That it is well written, as far as scientific publications go, is a bonus.
So does this book tell you everything you wanted to know about the pollination of Australian rainforest plants but were too afraid to ask? The short answer to that question is “no”, primarily because, as the authors state in their preface and repeat several times later in the book, “there are relatively few studies and data on the pollination of the Australian rainforest flora” (p. xi). With what information, you might then ask, have the authors filled its 200 pages of text? This book is really a general primer on plant reproductive biology and pollination ecology, illustrated by examples with an Australian rainforest bias. In this the authors have done a generally good job. Chapters on “Being a flower”, plant breeding systems, and pollination syndromes discuss the basic patterns, processes and concepts that dominate the floral biological literature, in a more lucid way than in the primary publications in which these ideas originated, mentioning in passing that some of these concepts have been criticised as potentially misleading by some scientists. Chapters on the spatial and temporal structure of rainforest and the influence of Australian vegetation history integrate the chapters on reproductive biology with the broader ecological context. These chapters are augmented by interesting and informative appendices on the relevance of pollination ecology for conservation, case studies of pollination in Australian rainforests and the role of large insects in pollination biology as well as several appendices of useful data.
The authors have also attempted to explain the evolutionary history of pollination with reference to land plant phylogeny in a couple of chapters called “Categorizing rainforest plants” and “Rise of the angiosperms, and archaic vascular plants in Australia’s rainforests”. It is here that plant systematists are likely to find themselves getting somewhat exasperated by a muddled and outdated approach that would lead some readers to think that phylogeny reconstruction is more of a dark art than an exercise in scientific inference. According to the authors, the simplistic division of angiosperms into monocots and dicots is problematic, not because the dicots are a paraphyletic nonentity but because “there are a number of angiosperms with the ‘wrong’ or an enigmatic number of cotyledons” (p. 33). “The ranking of monocots and eudicots remains unclear and their recognition within a consensus system of formalized classification is elusive” (p. 34), which would come as a surprise to the Angiosperm Phylogeny Group (whose first two classifications are included in the bibliography), for whom neither monocots nor eudicots have been elusive enough to evade placement in their classifications. Further on we are told that “primitive and possibly ancestral angiosperms do survive within Australian rainforests” (p. 36), and that “many such taxa are characteristic of Australian rainforests, which are putative centres of ancestral diversity and evolution” (p. 36). It should go without saying in 2010 that character states, not taxa, can be primitive, that higher taxa possess mosaics of primitive and derived character states and that it is highly unlikely that any extant species is ancestral to the rest of the angiosperms. Similarly, “the Elaeocarpaceae (e.g. Elaeocarpus, Peripentadenia and Sloanea) appear to have arisen in the Cretaceous and are considered ancestral to the order Malvales”. This is a remarkable assertion, not only for suggesting that one higher taxon can be ancestral to another but also because the Elaeocarpaceae have been firmly placed in the order Oxalidales in angiosperm classifications going back at least as far as APG I (Angiosperm Phylogeny Group 1998). “Our understanding of plant phylogenetic lineages is subject to the tyranny of the fossil record” (p. 39), despite the fact that plenty of highly resolved, well supported plant phylogenies have been constructed without reference to any fossils at all. To me, the most surprising claim in these chapters is that “based on phylogenetic studies, angiosperms are now seen as arising from multiple ancestral groups, perhaps as many as six, not from a single gymnosperm-derived stock” (p. 35) and “the current understanding [is] that flowering plants are derived from multiple ancestral non-angiosperm pathways” (p. 39). I have no idea where they found this notion, but to my knowledge, the last serious suggestion that the angiosperms are polyphyletic was made by Ronald Melville (1983), although other authors, such as A.D.J. Meeuse and Leon Croizat had earlier made analogous arguments on the basis of contentious interpretations of seed plant morphology. Every phylogenetic analysis of the angiosperms that I have seen since 1993 has strongly confirmed angiosperm monophyly, so the view presented here is seriously outdated.
My inability to work out where the authors were coming from here underlines this book’s greatest weakness: it has no in-text citations to the references in the copious bibliography. Citations were either never inserted in the first place, or (more likely?) were deliberately removed, perhaps in a misguided attempt to make the book appear less intimidating to a general audience. In a few cases, we are given the names of the scientists who did original research on which the text relies and then the reader can usually find the sources listed in the bibliography. However, in most cases there is no way to find the original sources efficiently. Unfortunately, this omission largely destroys the utility of this book as a reference work.
Despite my critical remarks, I do rate this as a useful book and value its presence on my bookshelf. As the “only game in town” it will be an essential reference for anyone working on the pollination biology of Australian species and ecosystems until a better replacement comes along. However, it is a great pity that it could have easily been made much more useful than it is. Hopefully, a second edition will be published that will have been critically read by someone with expertise in plant phylogeny and include in-text citations.
Angiosperm Phylogeny Group (1998). An ordinal classification for the families of flowering plants. Ann. Missouri Bot. Gard. 85: 531-553.
Melville, R. (1983). Glossopteridae, Angiospermidae and the evidence for angiosperm origin. Bot. J. Linn. Soc. 86: 279-323.