The Molecular Organography of Plants seeks to integrate the genetic findings of the last 20 years with morphological and evolutionary botany of the previous 100 years. Its author, Quentin C. B. Cronk, of the University of British Columbia, is a classically trained botanist and evolutionary biologist who has more recently worked in the integrative field of plant developmental evolution, making him well suited to write this text. The book's primary emphasis is morphological diversity and evolution, using the relevant developmental genetic work to highlight particular points or themes. In this way, it serves as a bridge between purely morphological works, such as Adrian Bell's invaluable Plant Form, and model system—centric developmental genetic texts, such as Leyser and Day's Mechanisms in Plant Development.
Cronk's approach is fundamentally morphological, and tracks the major organ systems: stems, roots, leaves, sporangia, and sporophylls. First, however, he gives a very useful overview of plant evolution and general evolutionary concepts (e.g., homology, heterochrony). This chapter lays a foundation for the rest of the book by covering the positions of major fossil taxa in the context of current phylogenetic hypotheses, and how they influence ancestral character state reconstruction. In addition, it establishes the historical perspective that is a consistent thread throughout. I particularly enjoyed the discussion of the different approaches to the problem of seed plant relationships taken by E. J. H. Corner and K. R. Sporne, and of what the first angiosperm may have looked like (issues that remain with us to this day). Cronk displays a sense of history and humor that is both entertaining and refreshing.
Each successive chapter follows a similar path, considering the possible origins of fundamental structures, their evolution in land plants, their various diversifications, and a relatively brief overview of their genetic underpinnings, often with useful findings or speculations on how these genes may have contributed to the evolution of the structure. I found the figures to be excellent overall, including the line drawings and color plates. Cronk goes to considerable lengths to introduce a wide variety of terminology, both developmental and anatomical. I might quibble with some of the uses—can we really say that mosses have protosteles? I've always considered the use of stele to be restricted to taxa with true vasculature, but that is part of the charm of botany—there is always room for variation in usage and interpretation. A more unfortunate mix-up occurs in the second chapter, where the words anticlinal and periclinal are reversed; I'm sure that the typo will be corrected in future editions, and as the terms are used properly elsewhere in the book, I imagine most students will properly reorient themselves.
Although “molecular” is in the title, this work is not a comprehensive developmental genetic text. I don't believe it was intended as such, but sometimes I did wish that extra space were committed to a more detailed explanation of the relevant genetic pathways or hypotheses. This was especially true for me in the section titled “Molecular theories for the origin for the flower,” in which a novel model involving APETALA2 was proposed but not explained in enough detail for me to completely grasp it. For this reason, I think the book may be most useful for the thousands of scientists coming from the molecular genetic side of the evolutionary development (evo-devo) divide. The many botanical tidbits and morphological oddities are certain to open the eyes of biologists whose experience with plants begins and ends with Arabidopsis and perhaps rice or maize. For those from the botanical and evolutionary side of evo-devo, The Molecular Organography of Plants represents a useful starting place and will help point them in the right direction with its extensive references. I can certainly recommend it for both types of scientists, particularly at the graduate level.