杏吧原创

I COULD not find a dull sentence or a wasted word in Robbin Moran鈥檚 A Natural History of Ferns. Read this excellent book and you will be left in no doubt that the world鈥檚 14,000 ferns, horsetails, quillworts and clubmosses are dynamic, important and interesting modern plants with much to teach us.

Moran, curator of ferns at the New York Botanical Garden, has travelled the world studying these plants. I cannot improve on the description of his aims in the book鈥檚 foreword: 鈥淚n each chapter there is a journey of mental exploration, moving from the level of description 鈥� passionate, detailed, wondering description, which is the essence of natural history 鈥� to the search for patterns, for mechanisms, for deep understanding.鈥�

Although the history of ferndom goes back some 340 million years, Moran emphasises the fact that most extant fern families and genera are of recent origin, having evolved after the appearance of the first flowering plants. The chapters on classification provide a readable up-to-date tour of the science that is revealing unexpected relationships, even for the horsetail, Equisetum, an ancient family that goes back relatively unchanged for 325 million years.

The book ranges widely over fern biology, evolution, ecology and history. We learn why the quillwort Isoetes needs the CAM type of photosynthesis to cope efficiently with daily fluctuations in carbon dioxide in its aquatic environment, and why ferns are better represented on islands than on large land masses. Moran describes the ecological significance of the 鈥渇ern spike鈥� at the Cretaceous-Tertiary boundary, when most ferns appeared, and gives a fine exposition of hybridisation and polyploidy and its importance in fern evolution. We are introduced to the aquatic fern Azolla, whose symbiosis with nitrogen-fixing bacteria makes it such a useful fertiliser for rice, and to the botanist who realised that his new species was an almost perfect match for a Mesozoic fossil.

Moran tackles the invaders too. In the chapter 鈥淭he molesting Salvinia鈥� he reveals how infestation of more lakes, ponds, canals and rivers worldwide by this free-floating giant water fern has been averted by the diligent research of botanists and entomologists in the field, in herbaria and in museums. This points up the importance of training expert taxonomists who can rapidly recognise different species.

Moran has brought together much information that is difficult to obtain elsewhere and presents it in an easy, natural style without jargon. This is science writing at its best. I recommend this book for the general reader and specialist, and it would be a fine tool for any natural science educator. Read it.