1 (=loB ìo J -iì Systematics and Biology of HemigeniaR.Br. and Microcorys R.Br. (Lamiaceae) Greg Guerin School of Earth and Environmental Sciences Discipline of Environmental Biology Submitted June 2006 for the Degree of Doctor of Philosophy in Science Systematics andBiology of Hemigenia R.Br. and Microcorl,s R.Br. (Lamiaceae) 11 Systematics andBiology of Hemigenia R.Br. and Microcorys R.Br. (Lamiaceae) Acknowledgements I thank my supervisors Prof. Robert S. Hill and Dr V/illiam R. Barker and everyone that assisted my studies, including Penny Mclachlan (field assistance), Patricia Guerin (latin translation), Rogier deKok (project idea), Ralph Foster (molecular laboratory techniques), Lisa Waters (line drawings), Andy Austin (insect identification), Ken Walker (insect identification), the Plant Biodiversity Centre of South Australia (host), staff of Adelaide Microscopy, the Department of CALM Western Australia. Systematics and Biology of Hemigenia R.Br. and Microcorys R.Br. (Lamiaceae) Contents I Introduction.............. 1.1 Introduction to Lamiaceae and rWestringieae..... 1.2 Taxonomicbackground.. 1.3 Phylogenetic analyses and classification .. I .4 Pollination biology . .. .. 1 .5 Conclusion ... 1.5.1 Summary...... 1,.5.2 Projectaims............. 2 FloralBiology......... Abstract........ 2.1 Introduction.. 2.2 Methods.. 2.3 Results . ... 2.3.1 Floral Types in Hemigenia and Mi.crocorys 2.4 Discussion.... .........24 2.4.1 Functional significance of floral variation. .........24 2.4.2 Bird Pollination................. .........30 2.4.3 Reproductive isolation ofpopulations....... 3t 2.4.4 Pollinator-specific reproductive isolation.. 33 2.4.5 Conclusion 34 3 Mericarpmorphology.. 39 3.1 Introduction.. 39 3.2 Preliminarymicromorphologicalstudy 41 3.3 Materials and methods.. 42 3.3.1 Evaluation ofmorphological variation.. 42 3.3.2 PhylogeneticAlalysis....... 43 3.4 Results 43 3 .4.1 Results of cladistic analysis. .. ... .. .. .. .. .. .. 52 3.5 Discussion.... 52 3.5.1 Conclusion 56 4 Taxonomic revision of Hentgenia R.Br. section Malleantha G.R.Guerin sect. no\¡.... 64 4.1 Introduction.. 64 4.1.1 Termirology and morphological interpretation ................ 65 4.1.2 Typification.. 6l 4.1.3 Nerv taxa 67 4.2 Taxonony and classification......,........ 69 5 Phylogenetic evaluation 5.1 Introduction.. 5.2 Methods 5.2.1 Moleculardataset:......... 5.2.2 Morphological dataset:....... 5.2.3 Combined dataset 5.3 Results 5.3.1 Moleculardataset:....... 5.3.2 Morphological dataset:....... 5.3.3 Combined dataset 5.4 Discussion.... 5.4.1 Comparison of rnolecular and rnorphological datasets 5.4.2 Combinedanalysis......... 5.4.3 Compalison with published phylogenies 5.4.4 Evolution ofmorphological characters................,,. 5.4.5 Towards an improved classif,rcation of the \rVestringieae............. 5.4.6 Conclusion 6 Summary and conclusions....,.....,........ 7 References Appendix A Molecular sequence data n Systematics and Biology of Hemigenia R.Br. and Mi.crocorys R.Br. (Lamiaceae) Abstract The genera Hemigenia R.Br. and Microcorl,s R.Br. (Lamiaceae, tribe Westringieae) have not been revised since 1870 and the existing taxonomy is inadequate. The current generic classification requires re-evaluation in light of more detailed knowledge of comparative morphology. The generic status of the related genaa Hemiandra R.Br. and Westringia Sm. also needs to be tested, as these genera share morphological characters with Hemigenia and Microcorys. Microcharacters were examined in over 60 species using SEM. The extemal morphology of mericarps (shape, attachnrent scar t)pe, sculpturing, exocarp cell shape and presence oftrichomes) provided significant cladistic data. A pilot study revealed that microcharacters of leaf surfaces were either invariable at this level or showed too much variation for systematic use. The floral biology ofthe gørera was studied since floral characters, particularly ofthe stamens, are used in the current classification. The stamens of Hemigeni.a and Microcorys have elougated anther connective tissue which bears one or two thecae, and the modified anthers are typically mobile on the filament. Field observations showed that insect visitors lever the anthers onto their bodies whilst accessing nectar. Bearding on the sterile end of the anthers catches adjacent stamens and levers them in unison. In the abaxial stamens of Microcotys,the anthers are reduced to sterile lobes, and these staminodes guide pollinators irto the flower. Identical staminodes are present in Ilestríngia and Hemigenia cuneifolia. The presence of a second theca on the abaxial stamens in Hemigeni.a was used by Benthan in the infrageneric classification. However, SEM revealed that the distinction was false and that Bentham's proposed pattem for this characte-r is erroneous. A taxonomic revision of Hemigenia section Malleantha G.R.Guerin sect. nov was carried out, and the treahlent included 26 species, including 13 new species. A cladistic dataset was compiled based on morphology, including floral and mericarp characters. A molecular dataset was constructed using fhe tt'nT-F region of the chloroplast genone. TLe two datasets were analysed both separately and combined using PAUP. The resulting phylogenies show both genera are polyphyletic. Evidence supports previous assertions thal Proslantlte¡z is sister to the other genera of the \üestringieae. A new classification is discussed, but firther data are required before this can be finalised. In particular, multiple DNA markers (including nuclear regions) need to be sequenced with a slightly larger sample of species. 111 Systematics and Biology of HemigeniaR.Br. and Microcorys R.Br. (Lamiaceae) Statement This work contains no nraterial which has been accepted for the award of any other deg¡ee or diploma in any university or other ßfüary institution and, to the best of my knowledge and belief, contains no material previously published or written by another person, except where due reference has been made in the text. I give consent to this copy of my thesis being made available in the University Library The author acknowledges that copyright of published works contained within this thesis (as listed below) resides with the copyright holder/s of those works. This thesis contains content from the following publications: Guerin G (2005) Floral biology of Hemigenia R.Br. and Microcorys R.Br. (Lamiaceae) Australian Journal of Botany 53: 147-162. Guerin GR (2005) Nutlet morphology of Hemigenia R.Br. and Microcorys R.Br (Lamiaceae). Plant Systematics and Evolution 254(I-2): 49-68. Signed Greg Guerin 15ú ofNovember,2007 lv Systematics and Biology of Hemigenia R.Br. and Mi.crocorys R.Br. (Lamiaceae) 1 Introduct¡on 1.1 lntroduction to Lamiaceae and Westringieae Lamiaceae (also known as Labiatae, the 'mint family') is a large, cosmopolitan family of flowering plants containing in the order of 200 genera and 5000 species (Wixk and Kaufmann 1996; Wagstaff et al. 1998) including well known aromatic culinary herbs such as Mint (Mentha spp.) and Basll (Ocimum spp.) (V/agstaff et al. 1998). The name Westringieae was applied by Bartling (1830) to a tribe of Lamiaceae genera endemic to Australia. The tribe now contains the genera Hemi.andra R.Br., Hemigenia R.Br., Microcorys R.Br., Prostanthera R.Br., Westringia Sm., and the monotlpic genus Ilrixoni.a F.Muell. Bentham (1834) applied the name Prostanthereae to the tribe and this name has often been used since. However it is a younger synonym of Westringieae. The tribe contains approximately 200 described species (Abu-Asab and Cantino 1993a). Prostantlte¡"a is the largest genus with approximately 90 species, and also the most studied with taxonomic revisions published in rnodern times (Conn 1984; Conn 1988). Westringieae exhibits morphological characters typical of the family such as opposite or whorled leaves, tubular, zygomorphic corollas, four stamens occurring in adaxial and abaxial pairs, a bifid style, and four indehiscent mericarps (here referred to mericarps) (Wagstaff and Olmstead 1997). An important morphological character of the Westringieae is the presence of elongated anther conlective tissue, the arrangement of which is used in the current generic classifi cation (Bentham 1 870). 1.2 Taxonomic background The genera Hemigenia and Microcotys weÍe named by Robert Brown (1810) following his expedition to Australia on board the HMS Investigator. George Bentharn and Ferdinand Von Mueller published many more species later in the 19th Century (Bentham 1848;Mueller 1859; Systematics andBiology of Hemigenia R.Br. and Mi.crocorys R.Br. (Lamiaceae) Mueller 1868;Bentham 1870;Mueller 1874;Mueller 1878; Mueller 1890;Mueller 1893). The frst and, to date, only taxonornic revision of the genera was conducted by Bentham (1870). Other authors have sporadically contributed descriptions of smaller numbers ofnew species (Lindley 1840;Barlting 1845;Luehmann 1898;Moore 1899;Moore 1902;Andrews 1904;Diels 1905;Moore 1920; Gardner 1931; Gardner 1942; Kenneally 1982; Conn 1986) and the tally now stands at 38 species of Hemigenia and 19 of Microcor))s. Not only has there been no revision since 1870 to tie together numerous publications of small numbers of new species, but also a number of variants have been identified as putative new species (Packowska and Chapman 2000), and recent flora compilations have highlighted the need for taxonomic revision in these genera, particularly in problem groups (e.g. Marchant et al. 1987). 1.3 Phylogenetic analyses and classification A number of independent studies of