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 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 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 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, , recent research has been on grasses, , 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), 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/-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. All 0.0% genera and most indigenous 2.6% 26.1% Brassicaceae species from New Zealand were sequenced (Mitchell 61.7% and Heenan, 2000). The outcome of this phylogenetic (evolutionary) Set research and subsequent reappraisal - - - <5% seeds of genus-level boundaries is that New Fig. 8 Controlled self-pollinations of Olearia ––– 6–50% Zealand has fi ve genera and about adenocarpa. Plants on the left-hand side ––– >51% seeds 30 indigenous species that belong show evidence of inbreeding depression. All to the family. Lepidium, Rorippa, and plants are 6 months old and the offspring of Fig. 9 Controlled cross-pollinations and self-compatible genotype C. seed set of fi ve Olearia adenocarpa Cardaminee (a genus now including Iti; genotypes (A–E). see Heenan, 2002), are cosmopolitan Since O. adenocarpaa is probably genera with mostly endemic New naturally self-incompatible, Zealand species. Notothlapsii is a New populations comprising large numbers Zealand endemic alpine genus with of plants (at least 50 individuals) two species, and Pachycladonn occurs are required to ensure successful in New Zealand and Tasmania. On outcrossing (Fig. 9). the basis of our phylogenetic research Once the breeding systems were and a reassessment of morphological resolved it became possible to characters, Pachycladonn was initiate conservation measures for O. recircumscribed to include the genera adenocarpa. Two areas comprising Fig. 10 The Canterbury Botanical Society Cheesemaniaa and Ischnocarpus. This about 36 hectares and including about planting out nursery-raised plants of Olearia enlarged genus now comprises eight adenocarpa.

New Zealand Garden Journal, 2008, Vol. 11(1) 5 also related to the well-known thale cress Arabidopsis thaliana (Fig. 12; Mitchell and Heenan, 2000; Heenan et al., 2002). Arabidopsis thaliana is indigenous to Europe, Asia, and north-western Africa. Signifi cantly, it is one of the few model organisms used A B C D for studying plant biology and was the fi rst plant to have its entire genome sequenced. Therefore it is a powerful tool for understanding the molecular biology of many different plant traits, including fl ower development. The monophyly3 of the Pachycladon complex and its relationship to E F G H Arabidopsiss has subsequently been Fig. 11 New Zealand species of a recircumscribed Pachycladon: A, P. enysii (was confi rmed by the analysis of additional Cheesemania enysii); B, P. fastigiata (was C. fastigiata); C, P. latisiliqua (was C. gibbsii); D, molecular markers (McBreen and P. stellata (was C. stellata); E, P. walliii (was C. wallii); F, P. cheesemaniii (was Ischnocarpus novae-zelandiae); G, P. exilis (was I. exilis); H, P. novae-zelandiae. Heenan, 2006). Based on the close relationship between Pachycladon endemic species (Fig. 11 Comparative research of and Arabidopsis, the existing A–H), with one additional species in morphological, molecular, and genetic Arabidopsiss genetic and molecular Tasmania (Heenan et al., 2002). data for these three genera could resources are likely to be well-suited test the origin, establishment, and to being used on Pachycladon. These Species of Pachycladonn show little species radiation of Pachycladonn in high-end molecular and genetic DNA sequence divergence and are New Zealand, and its subsequent resources make Pachycladonn an considered to have evolved relatively dispersal to Tasmania. In New ideal model genus for gaining a recently, only in the last 1.0–3.5 Zealand the geological and climatic wider understanding of the evolution million years (Heenan et al., 2002). prehistory has been dominated by of morphological characters, how It is now generally accepted that two phenomena. Firstly, the uplift species and adaptive plant radiations virtually the entire New Zealand fl ora of the Southern Alps of the South work, and to test biogeographic has originated from long-distance Island during the Pliocene and, hypotheses in a New Zealand setting. dispersal2 (e.g., Pole, 1994), and secondly, by Pleistocene glaciation. in the case of Pachycladonn the In addition to the phylogenetic DNA Both events have had a major impact closest relatives are the Northern sequencing work there is a large body on the evolution and distribution of Hemisphere genera Transberingia of other research on Pachycladonn that the indigenous New Zealand fl ora. and Crucihimalayaa (Fig. 12; Heenan further highlights its usefulness as a For example, centres of endemism et al., 2002). model genus. in the southern and northern South Cheesemania fastigiata Island have Cheesemania latisiliqua Cheesemania wallii been considered Pachycladon novae-zelandiae to be either Cheesemania radicata Ischnocarpus novae-zelandiae glacial refugia or Crucihimalaya wallichii Crucihimalaya himalaica Asia tectonically stable Crucihimalaya stricta Transberingia bursifolia areas. Species Arabis lyallii North America Arabis parishii Halimolobos perplexa ssp. perplexa of Pachycladon Halimolobos palmeri Sphaerocardamum stellatum occur in these Dithyrea californica Dimorphocarpa wislizenii regions and Nerisyrenia linearifolia Synthlepsis greggii have distribution Lesquerella stonensis Physaria acutifolia patterns that are Olimarabidopsis cabulica Fig. 13 DNA ‘fi ngerprinting’ (AFLP) plate Olimarabidopsis umbrosa of Pachycladon species. Each vertical lane Arabidopsis thaliana typical of other Arabidopsis lyrata ssp. lyrata represents a separate plant. Capsella bursa-pastoris species radiations Pseudoarabidopsis toxophila Turritis glabra in New Zealand, Yinshania henryi These studies include seed anatomy Lepidium flexicaule and are therefore Lepidium naufragorum and morphology (Garnock-Jones, suited to testing 1991a), breeding systems (Garnock- Fig. 12 Phylogenetic (evolutionary) tree (ITS maximum likelihood) these hypotheses. Jones, 1991b; Heenan and Garnock- of Pachycladon and related genera. In this tree, the previous An intriguing Jones, 1999; Bicknell et al., unpubl. names for the New Zealand species are used. This tree shows that data), embryology (Luo et al., 2003), Cheesemania, Ischnocarpus, and Pachycladon are intermixed (i.e., aspect of the they do not form separate groups) and as a consequence they have phylogenetic and DNA fi ngerprinting (Mitchell now been combined under the one genus, Pachycladon. research is that and Heenan, 2002). The DNA Pachycladonn is fi ngerprinting study used amplifi ed

2 See the article by Dawson and Winkworth (pp. 19–23). 3 A monophyletic group is a ‘natural’ group or lineage. See the article by Glenny et al. (pp. 8–9).

New Zealand Garden Journal, 2008, Vol. 11(1) 6 fragment length polymorphism data with different distributional and References (abbreviated AFLP) for most species substrate preferences. These include Allan, H.H. (1961). Flora of New of Pachycladon, and indicated that species that are restricted to either Zealand. Vol. 1. Government greater genetic variation was found schist (e.g., P. novae-zelandiae) Printer, Wellington. among populations and within species or greywacke (e.g., P. enysiii), and Croasdale, H. and Flint, E.A. (1986). than within populations (Fig. 13; others that are generalists (e.g., P. Flora of New Zealand Desmids, Mitchell and Heenan, 2002). Artifi cial cheesemaniii), occurring on a wide Vol. 1. Manaaki Whenua Press, Lincoln. interspecifi c F1, and some F2, hybrids range of substrates such as schist, have also been generated between greywacke, marble, limestone, and Croasdale, H. and Flint, E.A. (1988). species previously assigned to the basalt. Many of the adaptive plant Flora of New Zealand Desmids, genera Cheesemania, Ischnocarpus, radiations in New Zealand have Vol. 2. Manaaki Whenua Press, and Pachycladon (Heenan, 1999; Fig. utilised the diversity of habitats Lincoln. 14, 15). that are available on these different Croasdale, H.; Flint, E.A.; Racine, parent materials. We can use M.M. (1994). Flora of New these differences to test whether Zealand Desmids, Vol. 3. Manaaki Whenua Press, Lincoln. environmental factors are important drivers for speciation and if they are Edgar, E. and Connor, H.E. (2000). imposing selection. Flora of New Zealand, Vol. 5. Manaaki Whenua Press, Lincoln. Galloway, D.J. (1985). Flora of New Zealand Lichens. Manaaki latisiliqua ● Whenua Press, Lincoln. (Cheesemania) Galloway, D.J. (2007). Flora of New Zealand Lichens, Revised Second Edition: Including lichen- Interspecifi c hybrid combinations of A forming and lichenicolous fungi. species now assigned to Pachycladon. Manaaki Whenua Press, Lincoln. Garnock-Jones, P.J. (1991a). Seed A morphology and anatomy B of the New Zealand genera C Cheesemania, Ischnocarpus, Iti, Notothlaspi, and Pachycladon (Brassicaceae). New Zealand B Journal of Botany 29: 71–82. Garnock-Jones, P.J. (1991b). Gender Fig. 15 Leaf size and shape of the parents Fig. 17 Scanning electron micrographs of seed types in Pachycladon: A, winged dimorphism in Cheesemania wallii and an intermediate F1 hybrid: A, P. stellata; seeds, e.g., P. latisiliqua; B, wingless seeds, (Brassicaceae). New Zealand B, F1 hybrid; C, P. novae-zelandiae. e.g., P. novae-zelandiae. Journal of Botany 29: 87–90. The case studies presented here for Glenny, D. (2004). A revision of Oleariaa and Pachycladonn show that the genus Gentianellaa in New Zealand. New Zealand Journal of taxonomic research in New Zealand Botany 42: 361–530. has come a long way since the Healy, A. and Edgar, E. (1980). A C pioneering days of the botanists on B Flora of New Zealand, Vol. 3. Captain Cook’s fi rst voyages. While Government Printer, Wellington. Fig. 16 Leaf types in Pachycladon: A, some of the original methods remain heteroblastic (two or more different leaf types Heenan, P.B. (1999). Artifi cial unchanged, such as the careful on the same plant); B, serrated; C, lobed. intergeneric hybrids between examination of plant characters and the New Zealand endemic Species of Pachycladonn comprise the production of fl oras, there is also Ischnocarpuss and Pachycladon several distinct morphological a vast array of new tools and ways characters including, for example, (Brassicaceae). New Zealand of applying the basic taxonomic Journal of Botany 377: 595–601. leaf types (heteroblastic, serrated, information into a much wider context. and lobed; Fig. 16 A–C), growth habit Heenan, P.B. (2002). Cardamine lacustris, a new combination (monocarpic or polycarpic), fruit Acknowledgements replacing Iti lacustris (laterally compressed and the seeds I wish to thank my co-authors listed (Brassicaceae). New Zealand biseriate or terete and the seeds below and others for their support and Journal of Botany 40: 563–569. uniseriate), and seeds (winged or collaboration over the years. Thanks Heenan, P.B. and de Lange, P.J. wingless; Fig. 17 A–B). also to the New Zealand Journal (2001). A new, dodecaploid of Botanyy for their permission to Pachycladonn species mainly grow species of Unciniaa (Cyperaceae) reproduce some of the fi gures used in on shaded south-facing rock bluffs, from ultramafi c rocks, Surville this article. but they grow in soils derived from Cliffs, Northland, New Zealand. different parent material rock types New Zealand Journal of Botany (Heenan and Mitchell, 2003). There 39: 373–380. are three groups of Pachycladon

New Zealand Garden Journal, 2008, Vol. 11(1) 7 Heenan, P.B. and de Lange, P.J. Heenan, P.B.; Mitchell, A.D.; de Mitchell, A.D. and Heenan, P.B. (2004). Myrsine aquilonia and Lange, P.J. (2004). Arthropodium (2002). Genetic variation within M. umbricola (Myrsinaceae), two bifurcatum (Asparagaceae), a the Pachycladonn (Brassicaceae) new species from New Zealand. new species from northern New complex based on fl uorescent New Zealand Journal of Botany Zealand. New Zealand Journal of AFLP data. Journal of the Royal 42: 753–769. Botany 42: 233–246. Society of New Zealand 32: Heenan, P.B. and de Lange, P.J. Heenan, P.B. ; Smissen, R.D.; 427–443. (2006). Pseudowintera insperata Dawson, M.I. (2005). Self- Moore, L.B. and Edgar, E. (1970). (Winteraceae), an overlooked and incompatibility in the threatened Flora of New Zealand, Vol. 2. rare new species from northern shrub Olearia adenocarpa Government Printer, Wellington. New Zealand. New Zealand (). New Zealand Pole, M. (1994). The New Journal of Botany 44: 89–98. Journal of Botany 43: 831–841. Zealand fl ora – entirely long- Heenan, P.B. and Garnock-Jones, Heenan, P.B.; Lockhart, P.J.; distance dispersal? Journal of P.J. (1999). A new species Kirkham, N.; McBreen, K.; Biogeography 21: 625–635. combination in Cheesemania Havell, D. (2006). Relationships Webb, C.J.; Sykes, W.R.; Garnock- (Brassicaceae) from New in the alpine Ranunculus haastii Jones, P.J. (1988). Flora of New Zealand. New Zealand Journal of (Ranunculaceae) complex and Zealand, Vol. 4. Botany Division, Botany 377: 235–241. recognition of R. piliferuss and DSIR, Christchurch. Heenan, P.B. and Mitchell, A.D. R. acraeuss from southern New (2003). Phylogeny, biogeography, Zealand. New Zealand Journal of and adaptive radiation of Botany 44: 425–441. Pachycladonn (Brassicaceae) Heenan, P.B.; Knox, E.B.; Courtney in the mountains of South S.P.; Johnson, P.N.; Dawson, M.I. Island, New Zealand. Journal of (2008). Generic placement in Biogeography 30: 1737–1749. Lobelia and revised taxonomy for Dr Peter Heenan began a horticultural career at the Dunedin Heenan, P.B. and Molloy, B.P.J. New Zealand species previously (2004). Taxonomy and in Hypselaa and Isotoma and then Christchurch botanic conservation of Olearia (Lobeliaceae). New Zealand gardensgardens, gaininggaining a National adenocarpa (Asteraceae), a new Journal of Botany 46: 87–100. Diploma of Horticulture. In 1989, species from braided riverbeds in Luo, C.; Bicknell, R.A.; Heenan, he took a positit on at Landcare Canterbury, New Zealand. New P.B. (2003). Embryology of Research, LLincoln, in chc ara ge of Zealand Journal of Botany 42: two threatened species of the gardens and expeerimental 21–36. Pachycladon (Brassicaceae). nursery. He laaunnchc ed hiss botanicall Heenan, P.B.; de Lange, P. J.; Wilton, New Zealand Journal of Botany career at Landcarer Research A.D. (2001). Sophora (Fabaceae) 41: 171–178. soon afterrwards, gaining an in New Zealand: taxonomy, McBreen, K. and Heenan, MSSc at Missouru i annd then a PhD distribution, and biogeography. P.B. (2006). Phylogenetic through Canterbury Universitty. New Zealand Journal of Botany relationships of Pachycladon Peter Heenan is now one of New 39: 17–53. (Brassicaceae) species based on Zealand’s foremost contemporary Heenan, P.B.; Mitchell, A.D.; Koch, three nuclear and two chloroplast botanists. He has published more M. (2002). Molecular systematics DNA markers. New Zealand of the New Zealand Pachycladon Journal of Botany 44: 377–386. than 100 paperss, described some (Brasss icacceae e) complex: geg neric Mitchell, A.D. and Heenan,, P.B. 6060 plaant spep ciese , and contn inues cicircrcummsscriptp ion ana d relaatit ononsshhips (2000 0)0). Syssteme ataticic reelationnsshihipsps the ttradaditioon ofo boto ananiccal disscovery toto ArArababidopsis s.l.l. anand ArA abbisis s.ll. ofof New Zeaealaandd endndemicc annd dedescriiptp ion of Neww Zeaalandn ’s’s NeNew ZeZ allannd JoJoururnanal ofof Bototanany BBrrasa sicacacec aea infere reed frromo fl ora.a 4040: 54543–3–565622. nrnrDND A ITTS seseququenence datata.a Syyststememaattiicc Bototana y 252 : 988–1–10505.

New Zealand Garden Journal, 2008, Vol. 11(1) 8