American Scientist

SEEDS: A Natural History. Carolyn Fry. 192 pp. University of Chicago Press, 2016. $35.

Plant conservationists, horticulturists, plant ecologists, and the like face a perplexing public relations problem when it comes to their beloved subject: For many people, plant life—even though it is essential to the existence of all living things on our planet—may seem dull, especially in comparison with animal life. In 1998 American botanists James Wandersee and Elizabeth Schussler coined the term plant blindness, defining it as “the inability to see or notice the plants in one’s own environment,” leading to “the inability to recognize the importance of plants in the biosphere and in human affairs.” In the pages of Seeds, Carolyn Fry offers an almost certain cure for this malady.

The humble seed proves wonderfully interesting in her hands. As she worked on the book, Fry, an accomplished science writer, consulted with resident experts at the Royal Botanic Gardens, Kew, which also published the U.K. edition of her book. She outlines the evolution and natural history of seed-bearing plants (angiosperms and gymnosperms) concisely and accurately, building this story around individual accounts of people and plants in a way that will both inform and delight the reader. She has included superb and original images throughout the book, many of them illustrating, with light and scanning electron microscopy, aspects of plants and their biology that have rarely been presented as well. These images are not only a pleasure to view but also prove vital in conveying the book’s many compelling ideas and stories.

A particularly attractive feature of Seeds is how it presents its subject through a number of distinct access points, offering up discussions, for example, of particular plants or plant communities and highlighting key features with beautiful illustrations. Essays dealing with pollination and seed dispersal are especially well done. In a section about ballistic propulsion, for instance, Fry’s description of the action of awns , the slim bristles attached to wheat seeds (among others), identifies the clever mechanics involved:

While moist on the plant, the awns are held straight, but after flowering, as the fruits on the plant dry, the awns coil and form a spring mechanism that abruptly throws the seeds 18 inches . . . from the plant. Once free from the parent, the awns coil and uncoil with changes in relative humidity, physically drilling the seeds into the soil. Backward-facing hairs on the awn force the seeds to move in one direction, hence drilling continues even when the awn uncoils.

And her treatment of seed dormancy brings us right up to the limits of seed survival—which extend well beyond what readers might imagine possible.

Still, seeds are not invulnerable, and loss of genetic diversity may threaten their ability to survive as well as plants’ ability to produce seeds in the first place. Starting with the widespread adoption of agriculture some 10,000 years ago, humans have continually improved the characteristics of their chosen crops while simultaneously narrowing their genetic diversity. And less genetically diverse plants can prove more vulnerable to disease and more sensitive to environmental stressors. In recent decades, the narrowing of crops’ genetic diversity has become more pronounced in the face of increasingly large-scale and often relatively uniform agriculture. The development of agriculture at such scales is not surprising considering the yields required to meet the nutritional needs of the world’s 7.4 billion people—a number projected to climb by an additional 2.4 billion by midcentury. Feeding so many people while keeping crops’ genetic diversity above a certain threshold of potential vulnerability is a delicate balance.

Emphasizing our utter dependence on plants and therefore on their seeds, Fry weaves much of the narrative around efforts to save seeds, especially in seed banks around the world, thereby preserving a broad genetic diversity. She makes the agricultural importance of this work as clear as its ecological significance, describing how certain groups of researchers strive to conserve the genetic variety of crops while other groups work in parallel to conserve all plants. Modern methods of plant breeding, such as transgenics and CRISPR gene-editing technologies, have revealed the full range of genetic variability in plants to be fascinating and valuable in ways that we are only just starting to understand. Fry shows the special problems seed banks encounter in addition to solutions being developed, such as using cryopreservation at very low temperatures (–173 degrees Celsius) for short-lived seeds. Tissue culture is another promising prospect, especially for those plants that do not form seeds.

I do have quibbles here and there. In discussing apomixis, the ability of seed plants to reproduce asexually, the author states, “A relatively large number of plants appear to be apomictic; the trait has been observed in more than 400 flowering plant taxa.” Yet apomixis is actually comparatively rare among flowering plants, or angiosperms . Further, the evolution of herbs is conflated with the evolution of annuals, which occurred much more recently. And despite the book’s breadth, it leaves out some important topics, such as self-pollination and self-incompatibility. Such omissions don’t seriously harm the book, but they prevent it from being as definitive as it might be.

Regardless, Fry’s inclusive, well-rounded approach to Seeds—discussing botanical change over time as well as considering the seed in the context of the whole plant and its environment—is both refreshing and instructive. It is also quite welcome, given key trends that have moved in the opposite direction: namely, the diminishment of whole-organism biology in university curricula worldwide and, in many sectors of society, the loss of knowledge about the plants and animals that make our lives possible and delight our senses. For scientists and nonscientists alike, I strongly recommend this book.

Peter H. Raven is president emeritus of the Missouri Botanical Garden.