J. Adelaide Bot. Gard. 9: 1-286 (1986) A TAXONOMIC REVISION OF AUSTRALIAN ACANTHACEAE R.M. Barker c/- State Herbarium of South Australia, Botanic Gardens, North Terrace, Adelaide 5000 Abitract A revision of 28 native and naturalised genera of Acanthaceae is presented together with keys to infrafamilial, generic, specific and infra-specific taxa. There is a brief history of each genus and the morphology and floral biology of the genera have been discussed in comparative terms. Past infra-familial classifications have been reviewed and the placement of Australian genera within these is considered. Malesian material and literature have been consulted in order to establish correct names as far as possible; where Australian taxa extend into New Guinea, the New Guinea material has been included in the treatment. Lepidagathis Willd., Hemigraphis Nees and ?Peristrophe Nees are newly recorded along with the two generic segregates of Justicia &I., Calophanoides (Clarke) Ridley and Rhaphidospora Nees. A discussion of the generic delimitation within the complexes of genera sometimes placed under RueIlia and Justicia is presented. Species reinstated are Dipteracanthus australasicus F. Muell. (for RueIlia primulacea F. Muell. ex Benth., RueIlia corynotheca F. Muell. ex Benth. and Dipteracanthus corynothecus (F. Muell. ex Benth.) Bremek. ex W.R. Barker), Dicliptera armata F. Muell. (for D. glabra Decne.) and Dicliptera ciliata Decne. (for D. aff. leonotis Dalz. ex C.B. Clarke). The following new combinations have been made: Dicliptera australis (Brochosiphon australis Nees), lsoglossa eranthemoides (Justicia eranthemoides F. Muell.), Calophanoides hygrophiloides (Justicia hygrophiloides F. Muell.), Rhaphidospora cavernarum (Justicia cavemarum F. Muell.), Rhaphidospora bonneyana (Justicia bonneyana F. Muell.) and Rostellularia adscendens (Justicia adscendens R. Br.). This last name has been reintroduced for Australian material previously referred to Justicia procumbens L., J. clementii Domin, J. glaucoviolacea Domin and Rostellularia pogonanthera F. Muell. Within it, var. latifolia and var. hispida of ssp. adscendens are based on varieties described by Domin under Justicia procumbens L. The following new combinations are associated With changes in status: Di pteracanthus australasicus F. Muell. ssp. corynothecus (Ruellia corynotheca F. Muell. ex Benth.), Rostellularia adscendens (R. Br.) R.M. Barker ssp. glauco violacea (Justicia glaucoviolacea Domin), ssp. clementii and var. clementii (Justicia clementii Domin) and under ssp. adscendens, var. juncea (Justicia juncea R. Br.), and var. pogonanthera (Rostellularia pogonanthera F. Welt.). The following new taxa have been described: Acanthus ebracteatus Vahl ssp. ebarbatus, Staurogyne leptocaulis Bremek. ssp. decumbens, Dipteracanthus australasicus F. Muell. ssp. glabrata and ssp. dalyensis, Brunoniella lineanfolia and B. acaulis (R. Br.) Bremek. ssp. ciliala, Xerothamnella herbacea, Dicladanthera glabra, Dicliptera arnhemica and D. miscella,?Peristrophe brassii, Hypoestes sparsiflora and H. floribunda var. varia, val. yorkensis, var. velutina, var. cinerea and var. neoguineensis, Sarojusticia kempeana (F. Muell.) Bremek. ex H. Eichler ssp. muelleri, Rostellularia adscendens (R. Br.) R.M. Barker ssp. dallachyi and var. largij7orens of ssp. clementii (Domin) R.M. Barker. All names have been typified and areas where problems are still to be resolved are highlighted. NOTE: Dipteracanthus australasicus ssp. glabratus and the new combinations Rostellularia adscendens, R. adscendens ssp. clementii, var. pogonanthera and var. latifolia have appeared prematurely in Jessop & Toelken, Flora of South Australia edn 4, pp. 1318-1320 published on 1st August 1986. They are not validly published there. As intended (cf. International Code of Botanical Nomenclature 1983, article 34.3), the place of valid publication is within this treatment. J. Adelaide Bot. Gard. 9 (1986) Acanthaceae in Australia Contents I. I ntroduction 3 II. History of the family in Australia 5 III. Subdivisions of the.Acanthaceae and the placement of Australian genera 7 History of subdivisions of Acanthaceae. 7 Placement of Australian genera 8 IV. Relationships of the Australian genera I I V. Distribution of Acanthaceae in Australia 12 VI. Morphology 12 A. Characters of taxonomic importance in Australia 1. Habit and life span 12 2. Root system 13 3. Cystoliths 13 4. Stems and branches 14 5. Leaves (and bracts) 14 6. Inflorescence 15 7. Bracts and bracteoles 15 8. Calyx 16 9. Corolla 17 shape 17 size 17 indumentum 17 colour 17 10. Stamens 18 number and arrangement 18 filaments 18 connective 18 anther cell number 19 anther cell shape 19 anther cell arrangement 19 anther cell sutures 19 appendages 19 indumentum 20 pollen morphology 20 11.Ovary 20 12. Style 20 13. Stigma 21 14. C,apsules 21 shape, seed position and number 21 se-ed-bearing hoolcs 22 indumentum 22 mechanism of dehiscence 22 15. Seeds 23 16. Chromosome numbers 24 B. Pollination and floral biology 24 Allogamy 24 Autogamy 30 2 R. M. Barker J. Adelaide Bot. Gard. 9 (1986) VII. Taxonomic treatment of Australian genera. 32 Key to subdivisions of Acanthaceae in Australia 33 Generic circumscriptions of RueIlia and Justicia. 34 Key to genera in Australia 37 I. Thunbergia 40 Nelsonia 52 Staurogyne 60 Acanthus 64 RueIlia 75 Stephanophysum 79 Dipteracanthus 81 Brunoniella 95 Hemigraphis 114 Hygrophila 117 Barleria 125 Lepidagathis 128 Andrographis 130 Asystasia 132 Pseuderanthemum 139 Graptophyllum 156 Xerothamnella 166 Dicladanthera 171 Dicliptera 174 Peristrophe 191 Hypoestes 195 lsoglossa 226 Rhaphidospora 231 Calophanoides 235 Sarojusticia 240 Rostellularia 244 Anisostachya 276 Justicia s.l. 279 VIII. Acknowledgements 282 IX. References 282 X. Index to scientific names 287 Introduction The Acanthaceae of Australia are predominantly tropical or semi-tropical in distribution. As with any tropical Australian plant group, where the taxa are extensions of Malesian distribution ranges, there is often difficulty associated with the application of specific epithets. Malesian plant taxonomy is, on the whole, more fragmented than Australian, both because of the geography of the region and the different nationalities involved in its colonization and botanical study. There is frequently more than one name for a single species and the establishment of the correct epithet can be a time-consuming task. The Australian taxa have only rarely been reviewed in relation to Malesian species (e.g. Bentham 1868, and to some extent Bremekamp 1955, 1962, 1964). Despite the number of name changes which have been made in this revision of Australian taxa, it represents only a beginning. As with most revisions of families throughout Malesia, it is likely that some further changes will be necessary. This is not to say that Australian taxa are not real, but the status of some species (e.g. Nelsonia campestris, Hygrophila angustifolia, Hypoestes floribunda) and even certain genera (e.g. Brunoniella and Sarojusticia) may prove to be unjustified when full revisions are carried out. 3 J. Adelaide Bot. Gard. 9(1986) Acanthaceae in Australia Tribute should be paid to the work of C.E.B. Bremekamp in the Malesian area. Although my concept of the species and sometimes the genus is usually wider than that of Bremekamp, his work, particularly his notes on the flora of Java (Bremekamp 1948) has provided a framework which has proved invaluable in trying to place Australian taxa. In choosing tó adopt the segregate genera of both RueIlia and Justicia, I have followed the practice which is usually adopted in Malesia following Bremekamp's work there. This approach differs from that advocated in America and Africa, but until an overall revision of these two generic complexes is attempted there will be controversy about their rank. Whichever approach is adopted, any worker interested in placing a species in Rueilia or Justicia sensu lato will need to determine the relevant segregate group, whether as a section, subgenus or genus. In using the segregate generic names here, species relationships are immediately obvious and the alternative clumsy forms such as Justicia (Rhaphidospora) bonneyana or Rueilia (Brunoniella) australis are avoided. As elsewhere (Steam 1971) the segregate genera are very distinct on a regional basis and their use should not pose any difficulty to workers. There are three genera apart from segregate genera which are newly recorded for Australia. All three (Peristrophe, Hemigraphis and Lepidagathis) are from Cape York Peninsula and are at this stage, particularly in the case of the last two, represented by very little collected material. Consequently it has been difficult to name them at the specific level, although in the case of Hemigraphis and Lepidagathis they are almost certainly conspecific with species from New Guinea where these genera are in much need of revision. Material assigned to Peristrophe has been described as a new species. Since it lacks one of the generic characteristics and is somewhat atypical of the genus in Malesia it has only doubtfully been referred here. The two endemic and previously monotypic genera, Xerothamnella and Dicladanthera, the subtribal placement of both of which is uncertain, have both had a second species added. The most time-consuming tasks were the restructuring of the complexes Hypoestes floribunda and Rostellularia adscendens (= Justicia procumbens or Rostellularia pogonanthera of previous authors) and an unsuccessful attempt to do the same for the Pseuderanthemum variabile