Preface
PREFACE
The adventive flora, as distinct from the indigenous and cultivated plant floras, consists of those species which are not native in New Zealand and either grow spontaneously outside of cultivation – accidental introductions, or have escaped from cultivation and established in the wild – intentional introductions. In New Zealand literature, the adventive flora has been previously known as the alien, exotic, introduced or naturalised flora.
The term adventive is derived from the Latin "advena" a stranger, or immigrant. Thus it can be applied to all non-indigenous wild plants in New Zealand since all have had an "advent", but as with human migrants so with plants; some become fully naturalised, some never establish, being collected once and never seen again, or else, finding conditions marginal and lacking the means of dispersal to take them to more favourable situations, remain close to the site at which they first entered the country.
For some species there may always be doubt as to whether they are truly indigenous or adventive. As G. M. Thomson points out in his Naturalisation of Animals and Plants in New Zealand, 1922, pp. 10–11, a certain proportion of plants considered native to New Zealand could have been quite recent immigrants, especially species whose seeds can be distributed by wind or carried by birds. Such species "…are fairly abundant among those plants which are common to New Zealand and Australia and the probability is that many were thus introduced into these islands". Rushes, for example, have minute seeds and except for three endemic species all the native species are also found in Australia. However, most adventive species can be assumed to have arrived after 1769, when Cook first landed in New Zealand, and for some a fairly definite date of arrival is known. The development of the adventive flora has been a direct result of European occupation, and its dimensions in terms of area occupied and number of species and individuals is a measure of the extent and diversity of human activity. A wide range of plants of diverse botanical relationships, geographical origins and habitat requirements has been both intentionally and accidentally introduced, and now there are few sites at lower altitudes in which adventive plants are not prominent; many are so abundant and in such isolated places, as to present, especially to the non-botanist, every appearance of being native.
Just when the confrontation began between indigenous and adventive plants is not certain. It could even have occurred on a minor scale before 1769, both on the mainland and on outlying islands and involved weed plants which arrived as stowaways with food plants carried by the Polynesian voyagers. Whatever the pre-European situation, it was evident that, after a short period of organised settlement, European man had initiated obvious and disquieting changes in the vegetation.
Invaders are never popular. The aggressiveness, colonising ability, and the apparent capacity of an ever-increasing number of adventives to compete with, and even replace, some indigenous plants and communities made a strong impression on early botanists. A cautious prediction by Hooker in his introductory essay to the Flora Tasmaniae (1859, p. cv) was the basis on which others built. Hooker stated that many small genera of restricted distribution in Australia, New Zealand and South Africa would ultimately disappear because of the aggressive tendencies of northern hemisphere plants and man' s modifying activities. This supposed superiority of the northern hemisphere flora was accepted by Darwin, Wallace, Travers, and Cheeseman; their fear of what they termed the "Scandinavian Flora" was set out with apt quotations by G. M. Thomson (op.cit. pp. 525–32) who noted that Kirk combated the view that the majority of native plants would become extinct. By 1900, however, the turning point was reached and Cockayne' s sceptical attitude to the claimed superiority of adventive plants is summarised by Healy on p. 177 of The Natural History of New Zealand 1973 [G. Williams Ed.] and on pp. 278–9 of The Natural History of Canterbury 1969 [G. Knox Ed.]. Finally, 50 years later, C. M. Smith in Science in New Zealand 1957 [F. R. Callaghan Ed.] wrote, p. 135 " . . . the local botanist is now witnessing the phase of modification of the initial pioneer communities of adventive plants, and the initiation of the much more advanced phase of communities composed of an amalgam of indigenous and adventive elements". Within two centuries native and adventive plants had called a truce, but their treaty had still to be ratified in the Flora of New Zealand.
The preoccupation of resident and non-resident botanists over more than a century with the indigenous flora and the description of new species, meant that the adventive flora was neglected to a large extent. Many adventive species were recorded incidentally and in small numbers over the years, largely in papers devoted to the indigenous flora or to aspects of agriculture. Few botanists carried out work specifically on the adventive flora, and much of our information on the adventive flora overall and in terms of number of species recorded, we owe to the enthusiasm and contributions of J. D. Hooker, T. Kirk, Cheeseman, Thomson, Allan, and the Armstrongs, father and son. These workers not only gave substantial lists of adventive species in regional accounts of the indigenous New Zealand flora but they also provided papers specifically devoted to the adventive floras of provinces or other regions, culminating in 1940 in Allan's Handbook of the Naturalized Flora of New Zealand .
About three months after the publication of Volume II of Flora of New Zealand Raven and Engelhorn wrote in the New Zealand Journal of Botany (9, 1971, 218–9)"One of the most fascinating and controversial themes that runs through the literature of New Zealand botany concerns the interplay between the native flora, essentially that of an oceanic island, with the alien flora . . . In our opinion, there is no scientific justification for continuing to treat the alien flora of New Zealand as something apart from the native flora. There is no other country in the World in which all plants that reproduce themselves by natural means are not regarded as a part of the flora . . . "
The segregation of New Zealand indigenous species from adventive plants is first found in Hooker's Appendix II to the Flora Novae-Zelandiae (1855) where he gave a "Catalogue of European and other plants introduced into and now naturalised in New Zealand". Again in the Handbook of the New Zealand Flora (1864–7) Hooker listed at the back a certain number of naturalised, or apparently naturalised plants, and remarked (p. 757) "The rapidity with which European weeds . . . are being introduced into and disseminated throughout New Zealand is a matter of much surprise to all observers. Many plants are actually driving the native plants out of the country, and will, before long, take their places, and be regarded as the commonest native weeds of New Zealand." If Hooker had not been so greatly surprised, and rather shocked, and had included descriptions of adventive species in the body of the Flora, the pattern for segregation would never have been laid down. In other countries less vigorously invaded, adventive plants were included in the native floras step by steps as they became naturalised. If Kirk had finished his Students' Flora of New Zealand (1899) all would have been well since he described both indigenous and adventive species. But Cheeseman, obviously against his will, was instructed to follow in his Manual of the New Zealand Flora (1906, p. iv)". . . the general plan adopted in Sir J. D. Hooker' s Handbook . . ." and, as he says "With the view of keeping the work within the compass of one volume of portable size, I was further directed to confine it to the indigenous plants, thus departing from the plan followed by Kirk . . ."
Now when Cheeseman' s Manual was published in 1906, and again in 1925, no objection was expressed as far as we know to the arrangement whereby the native species were given full treatment in the main body of the work but adventive plants were listed only in an appendix at the back and yet the ratio of native to adventive species was even at that time only three to one. We suggest that this acquiescence was due in part to the tendency to regard the adventive plants as interlopers and in part to the intense interest in indigenous floras at a time when the study of plant geography and species distribution was at its height. Certainly when Cheeseman included Cyperus vegetus (C. eragrostis) in the body of the Manual (1925, p. 215) and noted ". . . there can be no doubt that it exists only as an introduced species in New Zealand . . . I retain it in the Flora because it has been twice described as an indigenous species, and on account of the remarkable fact that wherever found it presents all the appearance of a true native, and would certainly be taken as such by anyone unacquainted with its origin" he was criticised two years later by Cockayne and Allan (T.N.Z.I. 57, 1927, 64) who wrote "To us these reasons do not seem valid" and in the same paper (p. 61) they countered Cheeseman' s similar argument for retaining Geranium molle in the Flora, with the following remarks "None of these [Cheeseman' s] arguments seem to us to have any cogency whatever-it does not seem well to repeat the mistakes of the past, the description of this particular plant' s habitats is altogether too sweeping, and were the last reason valid [that it would be considered indigenous by a stranger] then exotic species after species would have to be admitted. That it is desirable that a flora of the exotic species occurring in New Zealand should be prepared we do not gainsay, but in view of the important principles involved, not least from the phytogeographic standpoint, and the misinterpretations likely to be made were Cheeseman' s procedure followed, we strongly deprecate any such admissions to floras explicitly claiming to deal with the indigenous plants of a country." They were quite correct because Cheeseman' s flora purported to be a purely indigenous flora.
This philosophy has changed. The tremendous increase in world travelling and communication has led to a marked increase in opportunity for adventives to settle in every part of the world so that all floras are becoming very mixed. With increasing studies of plant communities there is a feeling against any form of segregation of species so that a flora dealing with native plants alone or with adventive plants alone does not gain popular support. Flora writers in other parts of the world have had to take notice of these pressures. In their preface to the Flora of the British Isles (1952), Clapham, Tutin and Warburg wrote "There have also been changes in the flora itself . . . A considerable number of introduced plants have become well established and some of them are now widespread. All those which persistently occur in natural or semi-natural communities must be regarded as integral parts of the flora of the country and should be included in any account of it".
Ultimately a complete Flora of New Zealand must encompass both native and adventive groups in the one treatment. This volume represents a transitional stage. It would be impractical to reprint the whole of Volume II so soon, with the adventives welded into it; it would be reactionary to produce a volume dealing with adventives alone; we have tried to link Volumes II and III together, bearing in mind that Volume III will be principally used as an identification manual. Because the emphasis is on identification, it seemed that even though our title is Adventive Monocotyledons, we would have to include in some way many of the native species as well and that the keys should cover indigenous as well as adventive plants where appropriate. There are eight genera, Potamogeton, Cordyline, Juncus, Luzula, Centrolepis, Carex, Cyperus and Scirpus in which both native and adventive species occur. In the largest genera Juncus (31 adventive, 16 native species) and Carex (22 adventive, 73 native species) there are no features which immediately distinguish all adventive species from all native ones and consequently, for these two genera, a key a both adventive and native species, is absolutely essential. As well as the combined keys to adventive and native species, very brief description of native species with full details of distribution are provided, so that for the eight genera mentioned above, Volume III could be used alone. Because native species have limited treatment we have been able to include some additional information about these plants which was not available when Volume II was published, i.e. most, though not all, name changes are included, and for the genera of Juncaceae and Cyperaceae treated in this volume, new distribution records for natives species have been entered.
The pattern of combined keys is followed throughout. For instance, the families Liliaceae and Iridaceae are represented by both native and adventive genera though no one genus is represented by both native and adventive species. In the Iridaceae there is one native genus Libertia and a large number of adventive genera, mostly South African garden escapes, which are prevalent about Auckland; by contrast, adventive and native genera of Liliaceae occur in this country in roughly equal proportions. For Iridaceae and for Liliaceae a combined key to adventive and native genera is presented.
At the beginning of the books, families which contain only native representatives are covered in the keys to all cyperaceous, petalous and spathaceous monocotyledonous families and genera growing wild in New Zealand.
The problems of what categories of adventive species should be dealt with in the Flora is difficult to solve, although we have a fairly simple formula, "anything growing spontaneously outside a fenced area, or as a weed in a sown or planted community is an adventive." This is of course the widest view of adventive which one can take. The opposite extreme has been adopted by the editors of Flora Europaea , "Aliens are included only when they are effectively naturalized." Many of the adventive species treated here, e.g. Juncus bufonius, J. articulatus and J. effusus, have reached the full extent of their range and are found everywhere, but other species may just be commencing to spread actively due to some alteration in the environment and though not regarded now as effectively naturalised might well become so in very few years time. There is always a feeling that a reference work should be as free as possible from personal bias and if an arbitrary rule can be made as to what is to be included then it is all to the good. We should also admit that unlike our predecessors who had to limit their floras to "one volume of a portable size" we are dealing with a small group and have not been forced to be so rigorously selective. For rushes and sedges, then, we have fully described all adventive species which have ever been recorded in New Zealand, since plants in these two groups are all actual or potential weeds. For garden escapes we give full descriptions to those that have been collected more than once, and include brief notes, under the respective keys to genera or species, on plants that have been collected growing wild only once in New Zealand.
As in Volume II, Hutchinson' s arrangement, with some exceptions, is followed for the families, but genera within families are arranged alphabetically. Within small genera, species are arranged alphabetically too, adventives being placed first, followed by any native species. In larger genera, however, some morphological groups are separated out and the species then arranged in alphabetical order within these groups. The synopsis of orders at the beginning, lists all families and genera, both adventive and natives, giving the number of adventive and/or native species in each genus. To summarise: Volume III describes 22 families, 66 genera and 168 adventive species. The total number of monocotyledonous families (excluding grasses) in New Zealand is 35: 13 wholly adventive, 13 wholly native, 9 mixed: the total number of genera is 132: 58 wholly adventive, 66 wholly native, 8 mixed; the total number of species is 503: 168 adventive, 335 native.
The treatment of the adventive species in Volume III differs in small but significant ways from that of the native species in Volume II. Discussions of nomenclature and taxonomy such as are expected when dealing with the indigenous flora are unnecessary here except in difficult groups, like Sisyrinchium, where it is not yet possible to identify plants in New Zealand with any described species. Again, as with Lilium tigrinum, there may be controversy overseas over what name is currently acceptable for a species. We have had to make the best choice from the information available while pointing out existing alternatives. In general, we cite no synonyms, apart from names based on New Zealand type specimens; several adventive rushes and sedges were described as indigenous to New Zealand, for example, Juncus luxurians Col. described from a specimen of J. effusus L. there is even one adventive rush, the Australian Juncus amabilis Edgar, which had not been recognised in Australia at the time when the junior author described it as a native of New Zealand, despite its rather disjunct distribution, the type specimen coming from a rubbish dump, made more respectable to conform with native status by noting that it was near a golf course.
Although a full citation for citation for synonyms is not given, any names by which an adventive was formerly known in New Zealand are listed, some of these are, in fact, synonyms, but some were misidentifications. Common names used here are those from Standard Common Names of Weeds in New Zealand (N.Z. Weed and Pest Control Society [A. J. Healy] 1969).
For each adventive species a reference to the first published record is given, the titles of the papers being quoted in full in the "Bibliography of First Records". In this volume 33 species and 2 varieties are newly recognised as adventive to New Zealand and described in full. Although it is possible to establish the first record fairly accurately from the exhaustive search of relevant literature undertaken by the senior author, we must emphasise that the date of the first record has limitations in assessing the rate of spread and weed potentiality of a species: our field observations have shown that some species may be widely occurring and well established for quite a long time before they are formally recorded. The entries under "first collection" should be regarded as merely approximate. It may never be known what specimens of adventive New Zealand plants were sent to herbaria overseas by botanical collectors in the early days of the colony. The date of the first known collection is of most interest when it is very much earlier than the date of the first record.
Finally, since this volume is part of a continuing series of the Flora of New Zealand, the section Annals of Taxonomic Research is again included. This includes papers published between 1969-1976 and as in Volumes I and II is restricted to the indigenous flora. References to papers on adventive monocotyledons are given where appropriate in the notes under species descriptions.
ACKNOWLEDGMENTS
We wish to thank the Director of Botany Division for his continuing interest, and for sparing no effort to encourage us to complete this book. Every member of the staff, both present and past, has made some contribution to the work and we gratefully acknowledge their ready help; the extensive suites of aquatic plants collected by Miss Ruth Mason are invaluable and she made her knowledge of these plants freely available to us; we especially thank Mr A. E. Esler and his assistants Miss Sandra Astridge and Miss Shirley Bowman who have assiduously recorded and collected adventive monocotyledons in the Auckland district; we are grateful to many colleagues for innumerable specimens from new localities and for specimens of adventives new to New Zealand, even if at the time we may have expressed dismay at the thought of inserting yet another species into the manuscript; we are especially indebted to all our taxonomic colleagues for many exhaustive discussions on the relation of this volume to the two preceding volumes; for the text figures we wish to thank Mr K. R. West and his assistants Miss Gabrielle van Bree and Miss Robyn Conway, and for the colour plates we are indebted to Mr J. Somers-Cocks and Mr C.J. Miles; and we are most grateful to Mrs Barbara Matthews for undertaking the tedious checking of references, of species distributions, and of names of authors, and for her cheerful assistance in many other ways with the preparation and checking of the final manuscript.
We acknowledge our debt, in particular to Mr F. C. Allen, Ministry of Agriculture and Fisheries, and also to the many field officers of the Farm Advisory Division (originally Fields Division, later Extension Division) of the Department of Agriculture, now Ministry of Agriculture and Fisheries, who brought many new adventive species to notice over the years; officers of the New Zealand Forest Service; the Noxious Weeds Inspectors of County Councils; the specialist weed officers attached to stock and station and other commercial organisations; and officers of other statutory authorities who have contributed to our knowledge of adventive species.
Once again all the large herbaria in New Zealand have been used freely and we are indebted to the Directors and to the officers immediately in charge of each. We are also grateful to local collectors who have taken an interest in the adventives in their districts, in particular Mr G.B. Rawlings of Northland and Mr M. Heginbotham of Opotiki who have contributed many new records. We are also grateful to Dr A. E. Orchard, of the Auckland Institute and Museum, who has made a particular study of adventive Hedychium (Zingiberaceae).
In 1971 one of us (E.E.) visited the herbarium of the Royal Botanic Gardens, Kew
and we wish to thank the Director for the opportunity to check some early collections of New Zealand adventives. We are also glad to express our gratitude to Dr P. Ravenna of Santiago for his generosity in examining and commenting on specimens of Sisyrinchium; to Mr K. A. Beckett of Broxted, England, for assistance with the identification of Muscari; to Miss Rosemary Smith of Royal Botanic Gardens, Edinburgh, for confirming the identity of Hedychium flavescens; finally, we especially wish to thank Dr L. A. S. Johnson and Mrs Karen Wilson of Royal Botanic Gardens and National Herbarium, Sydney, who over many years have freely exchanged information and compared specimens of New Zealand and Australian rushes and sedges.
A. J. Healy
Elizabeth Edgar
Lincoln,
13 July 1977.
