Root and branch survey for truly cultivated tastes

The tropical traveller and keen gardener will find much to dig into in this arboreal heavyweight, says Ghillean Prance

This is an abundantly illustrated guide to all the commonest and some of the rarer tropical and subtropical trees and shrubs that are in cultivation around the world. It includes trees that are grown for their flowers, foliage, edible fruit, spices, timber and other uses. It is full of excellent high-quality colour photographs, mostly taken by the author, as well as silhouettes of more than 200 species showing their height and spread. There are also many other illustrations to help identify species.

The book begins with much useful introductory material. This includes a short section on the evolutionary history of trees, environmental factors influencing their growth, the hierarchy of botanical classification from division to cultivar and a guide on how to identify trees. The main part of the book describes in an encylopaedic fashion all the tree species included.

The brief second part is a series of most useful cross-reference tables to show the significant characteristics of the trees. This will be an invaluable tool for anyone wanting either to identify or to grow any of the trees. Such characteristics as soil type, tree height, growth rate, drought tolerance, salt tolerance and trees for humid shade are given in these tables. They also indicate which trees have showy flowers, the flower colour, time of flowering, fruit characteristics such as colour and edibility, toxic trees, trees for foliage and trees with interesting bark.

At the end there is a nicely illustrated guide to the morphological terms used here for leaves, flowers and fruit. This uses simple colour drawings and is followed by a glossary of scientific terms. All this makes it an easy book for the novice or the student to use.

Each entry is either for an individual species or for a group of closely related congeneric species. In the latter case, one species is described in detail and the others through short captions to the photographs. For example, in the case of the large genus Acacia, the sweet acacia, A.farnesiana, is the lead species and 15 others are also illustrated. In this way a large number of species are included.

Each description is accompanied by a standard table of features that will be of great use to anyone wanting to grow any of the species featured. The items included in the tables show area of origin; tree height; type of tree; conservation status; habitat; growth rate when flowering; salt tolerance; light; nutrient and soil requirements; hazards (for example, spines); problems (diseases); environmental interactions (pollinators); and propagation.

The descriptions are concise and relatively simple, and use vernacular terminology where possible. When technical terms are used they are explained in the glossary and colour guide at the end of the book. It is good to see the most recent concepts of plant family conservation adopted here. For example, the baobab ( Adansonia digitata ) is placed in the Malvaceae rather than in its former family, the Bombacaceae (which is wrongly spelt in the text). The African baobab is the lead species but other species of Adansonia from Madagascar and Australia are also illustrated and described.

The experience of the author in the field is obvious from the many observations about animal visitors to the plants. We read about such things as lorikeets feeding on the nectar of the Moreton Bay chestnut, how the long tubular flowers of the needle-flower tree (Posoqueria) are adapted to their long-tongued pollinator moths and how the flowers of Barringtonia are adapted to their bat pollinators. There is a large amount of natural history scattered throughout the book. Many important fruit trees are described such as cocoa ( Theobroma cacao , the source of chocolate), the pomegranate, the avocado, the Surinam cherry, the longan, the star fruit and the breadfruit, which will make this work of interest to the tropical fruit grower. Many different uses of the trees are given, varying from medicines to dyes, spices, timbers and oils. Altogether a wealth of information about tropical trees is scattered throughout this volume.

The coverage of species is worldwide from the tropics and subtropics and there is an adequate geographical balance that reflects the author's experience in many different countries. The coverage of species is good and the tropical traveller or gardener will find most of those he or she is likely to encounter in city streets and gardens. Palms are not included, but there are many books on palms and their inclusion would certainly need a separate volume. A few of the many tropical conifers are included but they are primarily a temperate forest group. I was surprised not to find the Paraná pine, Araucaria angustifolia , included among the four Araucarias selected. Brazilians will be disappointed to see their national tree Caesalpinia echinata called Indian savin tree rather than Brazilwood. I was also surprised to see that the genus Protea is not included: however, the silver tree Leucadendron argenteum and two Banksias in the same Proteaceae family from South Africa and Australia respectively merit entries. There are a few, tolerable, mistakes: for example, one of the pollinators of the cannonball tree is listed as Xylocarpa instead of Xylocopa.

This book will be most useful to gardeners who grow trees in warm climates, as well as to landscapers and arboriculturists. It is well researched scientifically and will be of considerable use to students of botany and horticulture. Tropical travellers will certainly find this work most useful to identify the trees they see, but it is too large and weighty a volume to take with them on a journey. I know that this is a book I am likely to refer to quite frequently.

Sir Ghillean Prance is former director of the Royal Botanic Gardens, Kew, and is scientific director of the Eden Project.