BOOK REVIEWS

Economic Native Plants in New Zealand

By S. G. Brooker, R. C. Cambie and R. C. Cooper
Published by Botany Division, DSIR, Christchurch, 1988
$NZ19.95

Reviewed by A. R. Ferguson
Division of Horticulture and Processing, DSIR
Private Bag, Auckland

Most of the world's really important crop plants have been grown for hundreds or even thousands of years and are now dispersed widely from their natural centres of origin. Many garden plants, especially those of temperate regions, have likewise spread around the world.

The early colonists who came to New Zealand brought plants with them. The Maori introduced some crop plants such as the kumara, taro and the yam and managed to keep them in cultivation, perhaps for a thousand years. The journals of Cook and of Surville indicate that the Maori also cultivated a small number of indigenous plants such as the kowhai ngutu-kaka (Clianthus puniceus) for its flowers and the karaka (Corynocarpus laevigatus) for its fruit.

The European colonists in turn brought many more economically important plants and they also brought ornamentals, plants that reminded them of the countryside and the homes that they had left, plants that made their new surroundings less strange and less threatening. The introduction of plants to New Zealand continues today. Our gardens are still very dependent on the plants brought mainly from Britain, not just the plants coming from Europe but also those that were introduced to Europe from North America, Asia or other Southern Hemisphere countries.

We are therefore accustomed to grow in the one garden, plants from different parts of the world, although there is now an increasing tendency to grow our own native plants. New Zealand plants are well adapted to our environmental conditions and they are resistant to, or tolerant of, many local pests and diseases. Many of them are attractive or interesting plants. More important, perhaps, they give a special and recognisably New Zealand ambience to our landscapes. Some plants have become almost ikons — the cabbage trees of Russell Clark, for example, leave us in no doubt that his paintings are of New Zealand. What was once strange or different now gives us a feeling of security, an awareness of place. Thus for New Zealanders one of the important attributes of our native plants is their very familiarity, the fact that we have grown up with them. As a result we tend to forget that in other countries these plants may actually appear strange, novel, or even exotic.

When we think of the origins of our garden plants we usually think of introduced plants and how they have come to us from other countries. Too often we forget that the movement and transfer of plants can be a two way process. The first part of Economic Native Plants of New Zealand provides a valuable and most interesting corrective: it gives a brief account of the early investigations of the New Zealand flora and then describes the attempts to introduce these plants into cultivation in Europe. This part of the book can usefully be read in conjunction with Bruce Sampson's Early New Zealand Botanical Art.

The exploration of New Zealand revealed a whole new flora to European science and it is difficult for us now to realise how exciting it must have been to be a botanist in the late eighteenth century, during the nineteenth century or in the first part of this century. New plants kept pouring in, first from the Americas, and then from Australasia, Southern Africa and Asia. It was not just the botanists who were excited — the interest of horticulturists was also aroused and collecting trips were made to bring back living material, especially from temperate regions where the plants are well suited to the climates of Europe and North America. Travelling to strange countries and obtaining herbarium specimens was hard enough but it was much harder to collect propagating material and get this home still alive. Subsequent propagation and establishment were even more difficult.

It is astonishing to learn from Economic Native Plants of New Zealand how little time elapsed between Cook's first voyage and New Zealand plants being grown, illustrated and described, and even offered for sale in Europe. The Endeavour arrived at what Cook named Poverty Bay in 1769 and seeds collected in New Zealand were back in England by 1771. The kowhai (Sophora tetraptera) had flowered by 1779 and was illustrated in a plate published in 1780. It was again illustrated the following year, this time in Curtis's Botanical Magazine, and was being offered for sale — by London nurserymen by 1783. Even more remarkable, Leptospermum scoparium was being offered for sale by nurserymen in 1778, the price of 7s 6d no doubt indicating its rarity. Some plants (e.g. what we now know as Haloragis erecta and Tetragonia tetragonioides) were described and illustrated from plants raised from seed. The authors detail how seeds from Cook's third voyage were widely distributed throughout Britain and to some of the great botanical gardens in Europe.

The more spectacular plants deservedly received much attention. The text accompanying the plate of the kowhai in Curtis's Botanical Magazine (tab. 167, 1791) stated, "A finer sight can scarcely be imagined than a tree of this sort ... thickly covered with large pendulous branches of yellow, I had almost said golden flowers; for they are of a peculiar richness, which is impossible to represent in colouring ...". According to Index Londinensis seven illustrations of the kowhai were published before 1800 and another seven by 1840. Clianthus puniceus, raised from seed gathered by the missionaries, obviously created an even greater impression when it first flowered — it was figured nine times between 1835 and 1838. John Lindley wrote in the Transactions of the Horticultural Society of London (2nd Series, vol. 1, 1835, tab. 22) that if Clianthus proved a hardy plant, "... its extraordinary beauty will render it one of the most valuable species that have been introduced of late years ...". It is unfortunate that many of our choicer plants are just not sufficiently hardy to survive European winters, but, as nurserymen such as Graeme Platt have suggested, this problem might be overcome by use of more suitable ecotypes. Less impressive plants were also figured, and Bruce Sampson in Early New Zealand Botanical Art notes that 135 New Zealand species have so far been illustrated in Curtis's Botanical Magazine, a fair representation of our flora.

The initial introductions of New Zealand plants to Europe were mainly as seed. Not all such introductions were successful: seed of the flax, Phormium tenax, was taken back to England by Banks and Solander but did not grow. It was not introduced till 1788 or 1789, when living plants were taken back to Europe, and it was being offered for sale by 1804. The flax is a very tough plant, however, and it was only after the invention of the Wardian Case that most plants were able to survive the rigours of the long sea voyage to Britain. Some of the first plants sent back in this way were collected by naval ships but soon nurserymen working in New Zealand started sending plants to Kew or to some of the enthusiastic private collectors.

To record the introduction of New Zealand plants into cultivation overseas requires painstaking searching of available nursery catalogues and the immense horticultural literature of last century and the first part of the twentieth century. Economic Native Plants of New Zealand provides a good introduction to that literature. There is also an account of the horticultural uses made of New Zealand plants in different countries. The Hebe has been particularly well received — a Hebe Society has been established in Britain to promote the genus, and several million Hebe plants are produced each year by Danish pot plant growers.

New plants continue to arrive in Europe. An advertisement in the May 1986 issue of The Garden (Journal of the Royal Horticultural Society) extolled Xeronema callistemon claiming that it was "... one of the world's rarest plants, which, since its discovery in 1924, has never been available commercially". Although described as a "must" for plant collectors the price of £32.85 per plant must surely have limited its appeal.

The growing of native plants in our own gardens receives comparatively brief mention. This is a topic that deserves fuller attention. The missionaries planted native trees and since then, enthusiastic amateurs have recognised the ornamental qualities of our flora. It seems, however, that it is only in recent years that horticultural fashions have changed and that native plants have become abundant in urban gardens. Perhaps there is a link between our enhanced awareness of a national identity and this greater appreciation of New Zealand plants.

I have concentrated on those parts of the book dealing with the scientific description and introduction of our plants. The main focus of the book is, of course, the New Zealand plants that are of real or potential economic value. The Maori of pre-European times used many indigenous plants but then once the Maori were here they really had little option. Bracken roots probably provided the main staple for many communities, and the most important plant they cultivated, the kumara, is not a native plant but one that they had brought with them to New Zealand. The early European visitors and settlers logged the forests and for a time flax was an important trade commodity, but apart from the grazing of the tussock grasslands of the South Island, there has been little sustained use of native plants in New Zealand agriculture of horticulture. The authors correctly point out that the use of our indigenous forests has largely been one of exploitation. Essentially all our vegetables, almost all of our pasture plants, most of our ornamentals, all our arable crops, and almost all the trees in our managed forests have come from other parts of the world. This is not really surprising. The New Zealand flora contains about 2000 species of higher plants and most of the world's food is provided by only 20 or 30 species. Even comprehensive lists of the plants used by man usually include only a few thousand species. New Zealand plants may be a valuable source of chemicals but most of the economic uses listed by the authors are limited, or are likely to be the basis of only small or very localised industries. I doubt that most of the potential uses proposed are worthy of much more than cursory examination. One interesting possibility, the use of cabbage trees to produce fructose, has probably been doomed by the appearance of a new disease.

Economic Plants of New Zealand has a somewhat utilitarian appearance as it has been produced by laser printer. However, the binding is strong, the text is clean and very legible and the real compensation is the remarkably low price — this book is most certainly a bargain! I noted a few typographical errors but most of these unlikely to mislead. I have not attempted to check the bibliography systematically, but those references I did check are correct. With almost five hundred citations, this will be a most useful starting point for future scholars. It is therefore a pity that the titles and full pagination of most papers have not been given. Furthermore, subsidiary authors are often listed inadequately as et al. and in other cases more details would probably make it easier to obtain material through interloans. There is a good index of plant names.

The illustrations are mostly taken from Thomas Kirk's Forest Flora of New Zealand of 1899, although some accompanying detailed sketches have, at times, been removed from the plates. The drawings have suffered in reproduction — all have a starkness lacking in the originals and those of Alectryon excelsus, Aristotelia serrata, Laurelia novae-zelandiae and Lophomyrtus bullata, in particular, have lost much detail and subtlety of shading. Nevertheless, these reproductions will have served their purpose if readers are encouraged to go back to Kirk's Forest Flora.

Economic Native Plants of New Zealand will be a useful reference for those wanting a quick summary of chemical studies into New Zealand plants. It also provides information on the former use made of these plants by the Maori or the European colonists. To those interested in the horticultural uses of our plants or in the history of the discovery of the New Zealand flora it collects together much new information. In some ways it is an irritating book because the often abbreviated comments force the reader back to the original literature. That, however, is also a measure of the book's success — I found that as I read it I was continually diverted to search for more information in a fascinating and diverse literature.

Horticulture in New Zealand: Journal of the Royal New Zealand Institute of Horticulture 1990 1(1): 24-26

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