The 2007 Banks Memorial Lecture: ‘Discovery and description’ of the New Zealand fl ora: a contemporary perspective Peter B. Heenan1 ‘Discovery and description’ Therefore, taxonomic New Zealand has a rich history research on many groups of botanical discovery and of New Zealand plants is an description of its fl ora, with the ongoing process, and detailed fi rst voyages made by Captain taxonomic study of a particular Cook including naturalists genus or other well-defi ned such as Joseph Banks, Daniel group may be published as a Solander, Johann Forster, and monograph. The most notable Georg Forster. Plants collected monograph in recent years was by these naturalists formed the made by David Glenny who backbone of the early fl oras of New studied the New Zealand gentians Zealand, including Florulae Insularum (Glenny, 2004). As a consequence Australium Prodromuss by G. Forster of his work, new species were and the Handbook of the New described, others were sunk into Zealand Floraa by J.D. Hooker. synonymy, and the New Zealand The more recent New Zealand fl oras gentians were transferred from the have relied much more extensively genus Gentianaa to Gentianella. on plant collections and research by Fig. 1 The fi ve-volume Flora of New For other groups, such as the Zealandd series. botanists resident in New Zealand, All provide a wealth of information herbaceous Cardaminee (bitter including T. Kirk (The Students’ Flora including detailed botanical cress), Craspediaa (woollyheads), and of New Zealand and the Outlying descriptions, illustrations, and Myosotis (the forget-me-nots) genera, Islands), T.F. Cheeseman (Manual identifi cation keys, which are used, there are no comprehensive, modern of the New Zealand Flora), and the for example, by students, farmers, and thorough taxonomic treatments. authors of the fi ve-volume Flora and horticulturists for understanding The ‘discovery and description’ of of New Zealandd series published New Zealand’s biodiversity. Popular the New Zealand fl ora is very much between 1961 and 2000 (Allan, 1961; books such as those on garden plants incomplete, and although more than Moore and Edgar, 1970; Healy and or weeds also draw on the source 2000 indigenous New Zealand plants Edgar, 1980; Webb et al., 1988; Edgar information provided in these fl oras. have been named it is estimated and Connor, 2000). These are the that about another 15% (some 300 vascular (so-called ‘higher plant’) The fl ora treatments provide the latest species) have yet to be formally fl oras (Fig. 1), but there are also fl oras information up to the time they are named and described. Some of these on New Zealand desmids (a group of published. Subsequent fi eldwork, unnamed species have been given freshwater green algae; Croasdale plant collections, and detailed study informal ‘tag names’ but these have and Flint, 1986, 1988; Croasdale of character variation and plant not been the subject of careful and et al., 1994) and lichens (Galloway, distributions provide new insights into rigorous scientifi c study which is 1985, 2007). There are also moss and relationships among plants (Fig. 2 required before a new species should liverwort fl oras nearing completion. A–E). be named. A B C D E Fig. 2 Plant taxonomists gather information using fi ve major resources: A, fi eldwork and plant collecting in the wild; B, growing plants on in the experimental nursery and grounds; C, laboratories for DNA sequencing and other work; D, herbaria where dried and pressed plants are deposited for permanent reference – the Allan Herbarium at Lincoln contains specimens dating back to the fi rst collections made by Banks, Solander, and the Forsters; E, the research library, which contains specialist botanical literature. 1 Landcare Research, PO Box 40, Lincoln 7640; [email protected] New Zealand Garden Journal, 2008, Vol. 11(1) 3 Since the early 1990s there has systems – Great Island in the Rakaia been a renaissance in fl owering plant River and an intermittent distribution taxonomy and from this time more along the Waimakariri River fl oodplain than 170 new species, subspecies, (Fig. 4). More than 600 plants are and varieties of New Zealand plants now known but the majority are have been named. Much of this severely browsed by cattle, sheep, recent research has been on grasses, hares, and rabbits (Fig. 5). This threatened species, and species-rich species was subsequently named as genera that lacked modern taxonomic A O. adenocarpaa and a conservation treatments. Although many of the new assessment recommended it be listed species have been previously known as Nationally Critical (Heenan and by tag names, several are completely Molloy, 2004). new discoveries that have been made by careful and detailed observation. From my research (and that of my collaborators) these include species such as Sophora godleyii (a new kowhai; Heenan et al., 2001), Uncinia perplexa (a new sedge; Heenan and de Lange, 2001), Arthropodium bifurcatumm (a new renga lily; Heenan A et al., 2004), Myrsine umbricolaa (a new matipo; Heenan and de Lange, 2004), Olearia adenocarpaa (a new shrubby daisy; Heenan and Molloy, 2004), Pseudowintera insperata (a new horopito or pepper tree; Heenan and de Lange, 2006), Ranunculus B B acraeus (a new buttercup; Heenan Fig. 3 Olearia adenocarpa: A, Dr Brian et al., 2006), and Lobelia carens Molloy examines a mature plant in the fi eld. Before conservation measures were (Heenan et al., 2008). implemented, there were only 11 mature When studying plant groups (e.g., plants capable of reproduction; B, botanical illustration of the new species. genera or species) for taxonomic research projects, many biological attributes are investigated in detail. Such attributes include, for example, leaf and wood anatomy, breeding systems, phenology (timing of C D different stages in the lifecycle such Fig. 6 Olearia adenocarpa: A, unbrowsed stems; B, browsed stems; C, cross section as growth initiation and fl owering), of an unbrowsed stem as seen through hybridisation, chromosome number a microscope showing the widely spaced and DNA variation. This information is growth rings; D, cross section of a browsed Fig. 4 Distribution of Olearia adenocarpa in stem. usually an essential and critical part the Waimakariri River fl oodplain. of the taxonomic decision making The scientifi c paper describing process, but it is also invaluable for this Oleariaa included information understanding other aspects of the of relevance to its conservation group, such as conservation biology biology, including plant growth habit, and evolutionary processes. age (growth ring counts; Fig. 6 Two case studies are now discussed A–D, Fig. 7), height, stem number, where general taxonomic information wood anatomy, and phenology. is utilised for the conservation of Furthermore, detailed description Olearia adenocarpaa and in the of its habitats and distribution was development of Pachycladonn as presented, as well as issues and a model plant for understanding opportunities for conservation evolutionary processes. management. At the time of its discovery, only 11 Olearia adenocarpa: conservation mature plants of O. adenocarpa An unnamed Oleariaa from the Fig. 5 Dr Brian Molloy examines a severely were thought to be capable of Canterbury Plains was fi rst browsed plant of Olearia adenocarpa. sexual reproduction and therefore recognised as distinct in August 2002 This small-leaved shrubby member research on its breeding system was (Fig. 3 A–B). of the daisy family is known only considered to be critically important to from the lower reaches of two river its long-term survival. New Zealand Garden Journal, 2008, Vol. 11(1) 4 Replanting inside the fenced areas with one-year-old nursery-raised plants was undertaken in August ) 2004 and July 2005 by the Canterbury Botanical Society (Fig. 10). This has mm ( only been partially successful, with about 10% of the plants surviving. To address this problem research is planned on the suitability of different potting mixes for nursery-raised plants, particularly in regard to Stem diameter growth and establishment after being planted out. Further research is also planned on the ecophysiology of O. adenocarpa, including water stress, photosynthesis, and respiration responses. Number of growth rings Fig. 7 Graph of the number of growth rings plotted against the stem diameter of Olearia Pachycladon: investigating a New adenocarpa. Zealand genus for understanding plant species and adaptive This research was undertaken and 250 plants have been fenced with radiations the species has been shown to stock- and rabbit/hare-proof fencing. New Zealand has several indigenous have a mixed breeding system that Since the fence was completed in members of the Brassicaceae (a includes self-incompatible and some August 2004, plants have had several family also known as the mustard self-compatible plants (Heenan et growing seasons and their recovery or cabbage family, or the crucifers). al., 2005). The self-compatible plants has been very successful. New shoots Genus and species relationships probably arose recently through the have emerged from at and below have traditionally been based on loss of self-incompatibility due to ground level; plants that were once morphological characters that are extreme selection pressure within severely browsed to only 2–3 cm high now known to exhibit considerable the small populations. The progeny are now 30–50 cm high, and now convergent evolution. Convergent of self-compatible plants have been fl owering and fruiting regularly. evolution is where plant groups shown to suffer from inbreeding may look similar due to a shared depression (a decrease in vigour or environment but are actually more fi tness as a result of inbreeding), as distantly related than it would seem. 70.1% about 33% of the selfed offspring 21.4% Therefore, in 1998 we began a were runts (Fig. 8). molecular study using DNA sequence 66.6% data (from a region called ITS) to further understand relationships of the New Zealand species.