When I began reading the scientific literature, (Gentle Reader: It would be impolite to ask exactly when that was, but for my undergraduates it was well “back in the day”) there were two places to go for a definitive look at any topic: journals and scholarly books. Our peers vetted both and both had long gestation periods. Journal articles were months or even a year in review and revision. Books took years to propose, review, write, edit and produce. Journal articles provided snapshots; but if you wanted synthesis of a topic by those who know it best, books were the place to go.
The 1970s and 1980s were a hey-day of modern scholarly books. Two classics on angiosperm evolution appeared during these decades: The Origin and Early Evolution of Angiosperms (1976, Columbia University Press) by Charles Beck, and The Origins of Angiosperms and Their Biological Consequences (1989, Cambridge University Press) by Else Marie Friis, William Chaloner and Peter Crane. Both were influential in staking territory, setting agendas, synthesizing past work and detailing paradigmatic hypotheses. But in retrospect, it was hard to write the definitive book because there was so much that we didn’t know. Our understanding of relationships among living plants was rudimentary, and the place of extinct lineages within this evolutionary framework was sketchy at best. And we had barely begun to tap the rich record of angiosperm mesofossils—fossils roughly 0.1 mm to 10 mm in size. So, it is certainly time to revisit the topic.
The 1990s saw the rise of the twenty-four hour news cycle and the Internet. Feeling the pressure to be more current, journals moved to on-line publication and editorial policies shifted to require peer reviews within just a few days. The pace quickened. Some of the reflection offered by long gestation was lost. My attention too shifted from definitive analysis to the latest breaking news. Even thought I am a great lover of books, my eye drifted from synthetic volumes to review articles (they were more current, after all) and the latest paper in my favorite electronic journal. What could turn me back to a book, the most current reference in which is an archaic 2011? A book can be definitive in ways that hurry-up publications commonly are not. But not all books carry such authority. So how do you write a definitive book for the 21st Century? Early Flowers and Angiosperm Evolution provides a blueprint.
Choose authors with perspective. The authors of a definitive book need not be scientific rock stars, (although Peter Crane is a Knight of the United Kingdom for his service to plants and their conservation) but they do need a perspective that is both broad and deep. Else Marie Friis brings depth. She has published more than 100 detailed and well-cited papers on Cretaceous flowers and the evolutionary patterns they reveal. Peter Crane brings breadth, with experience that spans a diversity of living and extinct seed plants and broad scale patterns in plant evolution. Crane was also among the first to experiment with adding fossil plants to phylogenetic studies when cladistic methods became popular in the 1980s. And the team of Friis and Crane has delivered quality in the past. Kaj Raunsgaard Pedersen adds the perspective of fossil pollen—key evidence in the early angiosperm story—to the mix.
Circumscribe the audience broadly. A danger for scholarly books is writing only to the other 35 experts in a narrowly defined field. A book on the early fossil record of flowering plants could easily take this bait. Early Flowers and Angiosperm Evolution avoids the pitfall by including enough background on each subject to make the volume accessible to a wider audience. The authors begin with introductions to the biology of angiosperms, the nature of their fossil record, and the Cretaceous stratigraphic, paleogeographic and paleoenvironmental context in which flowers first entered the fossil record. They provide enough context so that their arguments make sense even to readers who do not follow the angiosperm evolution debates closely. But be warned, Gentle Reader, Early Flowers and Angiosperm Evolution does not shed all of its jargon. Cladistics 101 is a prerequisite. And if you are not clear on the difference between an envelope and an integument, have your botanical dictionary at hand.
Be comprehensive. The definitive book must cover the entire field. Peruse this book to learn about the fossils you’ve missed reading only journals in your primary language or from a particular part of the world. Early Flowers and Angiosperm Evolution brings together the pieces and organizes them into a clear and comprehensive picture. Just about every fossil that has contributed to the story of Cretaceous angiosperm evolution is at least mentioned. I confess to having glazed over a bit somewhere in the middle of the parade of plant orders, but perhaps this 200-plus-page section should not be read linearly. It stands as a superbly annotated index of the data behind our current understanding of early angiosperm evolution.
Don’t stake too many controversial positions. Books are tempting. While a journal article will fall to shreds on the editorial floor if controversial ideas are not backed up with water tight evidence, books let authors stretch a bit—sometimes a lot—beyond the data. This can stimulate debate and ignite new research directions. Sometimes such books redirect whole fields; but more often they are quickly forgotten. But a scholarly book with staying power like Early Flowers and Angiosperm Evolution presents both sides of an issue. At some points—for example, the discussion about tools for reconstructing past climate using plant fossils—the authors fall over themselves to be even handed. But the intention is good and serves them well in the detailed reviews of current opinion on the evolutionary relationships among seed plants. Yet while I respect the balance the authors use, I was left hungry for a new idea.
Write well. This should go without saying, but more than a little scientific writing is just bad: wordy, cumbersome, jargon-laden, digressive and hard to understand. When I complain about such things, my students (and colleagues) roll their eyes and say that the ideas are more important than how they are presented. Wrong—but that’s a topic of another review. Early Flowers and Angiosperm Evolution is well written. The prose is consistently clear and concise. It is lean but not dense. The authors make their points, and all associated caveats, without tying themselves into grammatical knots. And every once in a while, there’s a lovely image: “The plethora of phylogenetic analyses of seed plants over the last decades has resulted in a forest of often seemingly contradictory trees, but nevertheless there are still some significant points of agreement.” (p. 149).
Make it beautiful. Editors push authors to keep the costs down. Authors try by recycling old drawings, going with low-contrast gray scale photographs, and skimping on illustrations in general. Thankfully, if Friis, Crane and Pedersen felt this pressure, they did not give in. This is among the most beautiful scholarly books I’ve seen in a long time. Outcrop pictures are clearly rendered in color, and maps and some diagrams include a touch of hue to enhance interpretation. (Although I confess that the shocking pink rise in angiosperm diversity [p. 464] is, well, shocking.) Headings and captions are printed in green, giving each page a splash of color that guides the eye. A single hand, Pollyanna von Knorring, did all of the abundant line drawings. Each original drawing is informative, interpretive and well-scaled to support and expand on the text. Having a single illustrator gives the book a visual unity that puts a big bow on an otherwise fine package. I learned a great deal just paging through the illustrations.
Move the conversation forward. A simple review of the previously published literature won’t make a book definitive. A book must move the conversation forward. Although 500 pages of careful synthesis suggests many remaining questions, this is not strength of Early Flowers and Angiosperm Evolution. In its last pages, Friis, Crane and Pedersen acknowledge that a lot has been learned in the last 50 years. But they shy away from setting priorities for future work. Yes, there are more fossils to describe, more localities to explore. This is a paleontological boiler plate. What are the big questions still seeking answers? What new techniques do we need to develop or apply? Or are we done? The alert reader will recognize that many questions remain. I wish the authors had taken another few pages to articulate their opinions.
This book was not everything I wished for when I unwrapped it. I wished for more new ideas and some forward-looking hypotheses. I wished for a bit more ecology and the role of various scales of variation (e.g., local versus regional versus global spatial scale) on the early angiosperm story. I wished for more on vegetative structure, a key place where plant meets environment. Wishes aside, this is a definitive book. It is detailed, accessible and offers a synthetic perspective from a team that has been thinking deeply about this topic for decades. And I hope this isn’t the last word. But the thing I love best about paleontology is that one fossil can rewrite everything we thought that we knew. Then we’ll be ready for the next definitive book.
Nan Crystal Arens is Associate Professor in the Department of Geosciences at Hobart & William Smith Colleges in Geneva, New York and has published on the ecology of early flowering plants.