Review
Flora of New Zealand, Volume I

By H. H. Allan. Government Printer, liv + 1085 pp. $5 5s.

Much work has been done on the plants of New Zealand in the third of a century that has elapsed since the second edition of Cheeseman's Manual appeared. As the results of this work are scattered through many periodicals in several languages, it was becoming increasingly difficult to work with any confidence on the taxonomy or distribution of the plants of these islands. With the issue last year of volume 1 of Allan's Flora, this work and much more original research has been collected together and assessed. Further work on these aspects of botany has been given a newlease of life.

New Zealand may take justifiable pride in this excellently produced volume, and all its users should feel gratitude to Dr. Allan for his patient work, and also to the many botanists associated with him. A particular debt is owed to Miss Lucy Moore who collaborated with Dr. Allan for many years and upon whom fell the task of completing the manuscript after Dr. Allan's death, more than three years before publication, and who finally prepared the book for the press.

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This treatment of the plants of New Zealand compares favourably with the major floras of the world. Its high standard is due to two main factors. Firstly, a clear and uniform plan was adopted on which to model the account of each group and was then adhered to rigorously. Secondly, the all importance of accuracy of detail has never been lost sight of. This applies not only to the descriptions of plant characters and distributions, but also to the niceties of nomenclature. The inclusion of a reference to the type specimen illustrates both these points. Many floras do not include this feature, but it has been the failure to refer to the type so often in the past which has resulted in the uncertain application of so many names.

But the most pleasing feature of the book is that it does not limit itself to the information normally expected in a flora. It is an invaluable book of reference to New Zealand botany. This is partly due to the introductory sections, particularly the chronological list of research papers, but mainly to the inclusion of notes in small type at whatever point they seem appropriate. One has only to look at the pages following the systematic treatment of Coprosma to realise how much these notes enrich the book. They are not only informative, but should stimulate the imagination of students by repeatedly drawing attention to problems requiring investigation.

No flora can be regarded as final, and difficulties which have not been completely resolved are frankly stated. Anyone using the book therefore feels generally confident in the soundness of the decisions which had to be taken on nearly every page. The confidence is greatly strengthened when he finds how much light has been shed on such difficult groups as Myosotis, and the Hebe complex.

Many users on first handling the book remark unfavourably on the very thin paper. It must be admitted that the constant effort to separate these pages can become exasperating, but I believe an impossibly thick volume would have been a greater evil. Once we have become used to the new method of presentation of information on distribution by reference to degrees of latitude, we shall probably prefer it to the descriptive method used by Cheeseman. But South Island botanists at least will miss any regular indication of east to west distribution which is often quite as distinctive as northern and southern limits.

The order in which the families are arranged is perhaps a matter of slight importance, though it is fortunate that, if Hutchinson's order had to be used, his second and more revolutionary scheme was published too late for use in this volume. However, some departures from more usual sequences are not explained. For example, the Lobeliaceae are separated from the Campanulaceae by two small families, and the Cornaceae stand between the Araliaceae and the Umbelliferae.

The key to the families of Dicotyledons will be of use to students who have realised that every taxonomist must be self-taught. page 42 It is admittedly an artificial key and most characters used are clear-cut and practical. It is all the more unfortunate that the first pair of characters in the key is quite unrealistic. Except for stem parasites, to answer this question, every plant considered (including forest trees) would have to be dug up and its roots carefully examined. The same criticism applies to the key to genera. It is doubtful how useful this second key will prove to be. A beginner should use the key to families and then determine the genus by means of the keys that are given under each family, while a more experienced worker, when faced with a plant of unknown genus, should go straight to the few families which he considers possible.

The choice of generic limits must remain a matter of convenience into which the personal element will enter. In large families artificial generic limits are often useful and the treatment of the Compositae has been conservative in this respect. The several inter-generic hybrids known among the New Zealand Gnaphaleae suggest that Raoulia. Helichrysum, Leucogenes, and Ewartia are doubtfully distinct. This cautious treatment has not been applied uniformly. The generic limits in the Araliaceae seem less clear now than formerly. Stilbocarpa formed a group uniform in habit and distribution, and sharply divided from its relatives. The separation of Kirkophytum would be justified if some clear differences were present, but the shape of the fruit apex appears very similar in all the plants concerned. In separating Neopanax (a new name for Nothopanax) from Pseudopanax Dr. Allan still relies on the number of the loculi, but has manipulated the division so that Pseudopanax includes P. lineare. This is an improvement on the arrangement in Cheeseman. To achieve this, however, he has been obliged to transfer Nothopanax edgerleyi to Pseudopanax away from its close relative N. simplex. Unless some other basis for separating these two genera can be found, it would be safer to treat them as one group under the name Pseudopanax. In any event the statement that Neopanax is endemic overlooks the Chinese plants currently regarded as species of Nothopanax.

There is one feature which is an exception to the general consistency of the book. Whenever a variety is recognised within a species it is advisable for the remaining section of the species also to be treated as a variety. This avoids confusion by providing names for both portions of the species while leaving the specific name to be used for the group of varieties as a whole. This practice is often adopted, as in Coprosma propinqua, but it is often neglected as in the preceding species. Coprosma parviflora.

The overall impression left after using this work is that for most groups progress has been pushed as far as possible by traditional taxonomic methods. Here as last we have a foundation upon which individual workers can confidently build detailed studies of small page 43 groups. Now that Dr. Allan's work has been published, further progress in the understanding of the Dicotyledons of New Zealand will rarely be made without the experimental approach, as is so often stressed in this flora. The eagerness with which the volume on the Monocotyledons is awaited is a measure of our satisfaction with this first volume. Some amateur botanists may be intimidated by the austere presentation that any flora demands, but they should realise that books which attempt to make things easy as often as not lead their users into unsuspected difficulties.