INTRODUCTION TO THIRD EDITION (AusGrass, Sharp & Simon, 2002)
A considerable amount of taxonomic work on the grasses has been undertaken since the second edition to this key, now out of print. A third edition is now appropriate in the light of this new knowledge about the family. The publication of this interactive key, with the benefit of an additional information system in html format, provides a unique opportunity of updating the dichotomous keys, while at the same time presenting a different avenue of identification which may supply confirmation of an identification undertaken by means of the interactive LucID key. In addition the html feature enables one to access the fact sheets on the grass species by means of a single mouse click.
Many of the nomenclatural changes in the grasses in recent times, particularly at generic rank, result from recent advances of taxonomic investigation using cladistic methodology based on both morphological and molecular data. This has gained momentum in the era between the first international symposium on grass systematics (Soderstrom et al. 1987) and the third symposium in Sydney (Jacobs & Everett 2000). As a result a number of phylogenetic lineages are now formally recognised.
Examples of papers where nomenclatural changes have been made following cladistic analysis are the danthonioid genera Austrodanthonia, Notodanthonia, Rytidosperma and Joycea (Linder & Verboom 1996, Linder 1997), the placing of Diplachne into synonymy with Leptochloa (Snow 1997, 1998), the recognition of the genera Walwhalleya and Homopholis as separate lineages (Wills, Whalley & Bruhl. 2000), the application of new names (Austrostipa, Achnatherum and Jarava in Australia) to lineages within the stipoid grasses (Jacobs & Everett 1996, 1997; Jacobs et al. 2000) and the splitting of the traditional genus Sorghum into the segregate lineages under the genera Sorghum, Sarga and Vacoparis (Spangler 2000, Spangler in press). Current work on the ehrhartoid grasses (Verboom et al. 1998 and pers.com.) reveals there to be a number of clades within this group, but the decision as to how to apply Linnean nomenclature to the lineages, still has to be resolved. However the decision to place Microlaena and Tetrarrhena into synonymy with Ehrharta (Willemse 1982) is not followed here and the three genera are still recognised as being separate.
On the other hand there have been some nomenclatural changes applied to the species of some large Australian genera (the Brachiaria - Urochloa and Paspalidium - Setaria complexes) based, to me at least, on rather preliminary, and what appears only phenetic evidence (Webster 1987, 1995). The move of most species of Brachiaria to Urochloa is followed by a number of workers (references in Simon 1992, Ashalatha & Nair 1997, Morrone & Zuolaga 1993, Veldkamp, 1996) as well as in floristic accounts (Jacobs & Wall 1993, Macfarlane 1992). The placement of all species of Paspalidium in Setaria, has been followed by some authors (Veldkamp 1994), but not others (Davidse & Pohl 1992), but has recently been taken up by an Australian publication (Shepherd, Richardson & Richardson 2001). However I feel these changes are premature pending a more in-depth cladistic investigation, including all species, with apomorphic morphological characters shown on a clearly defined topology. For these reasons I have treated species of these genera in their traditional positions.
In addition to research into the boundaries between genera based on cladistic methods, there have been a number of conventional taxonomic revisions of large Australian genera since 1993, where many new species were described - Eriachne (Lazarides 1995), Eragrostis (Lazarides 1997a), Triodia (Lazarides 1997b) and Sporobolus (Simon & Jacobs 1999). The circumscription of these genera, based on morphological characters, is relatively stable, although investigation of non-morphological characters are revealing that boundaries based purely on morphology are not as rigid as once originally thought.
The boundary between Eragrostis and Sporobolus is blurred, with the latter genus thought to be derived from the former, with the loss of lateral nerves and the reduction of the spikelet to one floret. Thellungia lies on the border and could be accommodated in Eragrostis on morphological evidence and Sporobolus on molecular evidence (Ortiz-Diaz & Culham 2000). For this reason I have retained it as a separate entity, pending further work.
In the genera Triodia and Plectrachne morphological characters of glume length in relation to floret length and the degree of lobing and awn length of the lemma were useful for distinguishing feature when there were few species known. However these characters showed greater heterogeneity when more species became known and were described that Lazarides (1997b) decided to place them together. Further cladistic work on this group based on molecular data (Mant et al. 2000) supports the breakdown of the division between Triodia and Plectrachne, but suggests there may be a case for the recognition of new “genera” on the basis of anatomical characters.
In a recent revision of Chrysopogon for Malesia (Veldkamp 1999), the previously recognised morphological differences between Chrysopogon and Vetiveria were shown to be rather insignificant and the earlier name taken up for an expanded genus uniting the two. This includes the ecomonically useful “Vetiver Grass”, now called Chrysopogon zizanioides.
In some Australian genera a few new species have been published since 1993. These are two species of Aristida (Simon 1994), a species of Micraira (Clark et al. 1994), and a species of Echinochloa (Michael 1999). A number of further new species are being prepared for publication and will be referred to by manuscript names in this key. Furthermore the circumscription of the group of taxa allied to and including Agrostis is being in the process of being brought into line with the New Zealand treatment of Edgar and Connor (2000) (Jacobs 2001).
Notes on format
Naturalised entities are indicated by an asterisk (*). Distribution of entities for Australian states are indicated by the abbreviations of the states:-
NSW - New South Wales VIC - Victoria TAS - Tasmania NT - Northern Territory
SA - South Australia WA - Western Australia QLD - Queensland
The couplets have been constructed to be brief and unambiguous and they are based almost entirely on flowering material. When a single character was considered to have conclusively separated a taxon from its partner in a couplet this was considered adequate from the point of view of identifying the taxon. Two or more characters have only been used in couplets where there is a need for more than one character to distinguish a taxon from the opposing member of a couplet. In a few cases triplets have been used instead of couplets where it was thought the key data was better expressed this way.
Where an entity is referred to by a collector's number, this entity is thought to be new and is either in the process of being published or will be some time in the future.
INTRODUCTION TO FOURTH EDITION (2012)
Since 2002 there have been some changes to the generic membership of all subfamilies occurring in Australia (except Pharoideae) to varying degrees. These changes relate either to a new classification for a subfamily, the updating of generic circumscription following taxonomic research or the expansion of the number of genera for a subfamily due to naturalisation from elsewhere.
These changes are likely to continue as the present trend of molecular phylogenetic research continues in the family, particularly as the techniques for doing so become relatively inexpensive and the sample size of the number of species analysed increases.
The specific changes between the classifications of 2002 and 2012 are listed under each subfamily
Stipeae Achnatheum to Ameliochloa (Arriaga & Barkworth 2006)
Meliceae Addition of Melica (J.P.Jessop 2009)
Triticeae Addition of Anthosachne for Australian species formerly placed in Elymus (Barkworth & Jacobs 2011), and the replacement of Lophopyrum by Thinopyrum (Henwood & Weiller (2009).
Poeae On the basis of molecular work species of the genus Austrofesctuca are now placed in Poa and Hookerochloa (Gillespie et al, 2005, Jacobs et al. 2008).
Phaenospermateae The placement of Anisopogon in this tribe (from Stipeae) (Kellogg pers.com.)
III. BAMBUSOIDEAE Australian species of what were formerly included in Bambusa are now placed in Bambusa, Nelolobea and Muellerochloa (Franklin 2008).
Potamophila is placed in the tribe Zizaniinae and not Oryzeae (Kellogg 2009, Tang et al 2010)
Stipagrostis is added, following a recent discovery of S. cilata (Desf.) De Winter in Central Australia (Albrecht, pers. comm).
CENTOTHECOIDEAE is subsumed into the Panicoideae (see under that subfamily).
VI. CHLORIDOIDEAE. The classification of Peterson et al. (2010) presents a number of changes in this subfamily, shown below.
Eragrostideae: Cotteinae. Enneapogon
Eragrostidinae. Ectrosa, Eragrostis, Heterachne, Psammagrostis
Cynodonteae: Incertae Sedis. Acrachne, Dactyloctenium, Perotis
Trioidinae: Monodia, Symplectrodia, Triodia
Eleusinae: Astrebla, Austrochloris, Brachyachne, Chloris, Cynodon, xCynochloris, Dinebra, Eleusine, Enteropogon, Eustachys,
Leptochloa, Lepturus, Microchloa, Oxychloris
Tripogoninae: Eragrostiella, Tripogon
Zoysieae: Zoysinae: Zoysia
Sporobolinae: Crypsis, Spartina, Sporobolos, Thellungia
VII. DANTHONIOIDEAE. This follows the recent classification of the subfamily by Linder et al (2010), where Austrodanthonia, Notodanthonia and Joycea are subsumed into Rytidosperma. The genus Pentaschistis has also been subsumed into Pentameris. In AusGrass the entry under Arundinoideae for this group should have had a tribal spelling Danthonieae, as it was regarded as a tribe there.
Amphipogoneae. Diplopogon has been synonymised under Amphipogon (Macfarlane 2005).
IX. MICRAIROIDEAE. This subfamily was reinstated and emended by Sanchez-Ken et al (2007) to include the tribes Eriachneae, Micraireae and Isachneae. The former two tribes were formerly regarded as Incertae Sedis in AusGrass and the Isachneae (with genera Isachne and Coelachne) has been moved from the subfamily Panicoideae. Cyrtococcum, was previously placed in Isachneae but this is erroneous and is regarded as belonging to the Panicoideae.
The recent work on this subfamily by Sanchez-Ken and Clark (2010) and more particualrly on the Paniceae by Morrone et al (2011) has produced a classification that is greatly changed from that used before. The subfamily Centothecoideae has been subsumed into the Panicoideae.
Phylogenetic work on this tribe is still to be completed (Kellogg pers. comm.) The tribe is monophyletic and molecular data indicate that the tribe is the result of a rapid radiation throughout the world.
Andropogon, Apluda, Arthraxon, Bothriochloa, Capillipedium, Chionachne, Chrysopogon, Clausospicula, Coix, Cymbopogon, Dichanthium, Dimeria, Elionurus, Eremochloa, Eulalia, Germainia, Hemarthria, Heteropogon, Hyparrhenia, Imperata, Ischaemum, Iseilema, Microstegium, Miscanthus, Mnsiethea, Ophiuros, Pogonatherum, Polytrias, Pseudopogonatherum, Rottboellia, Saccharum, Sarga, Schizachyrium, Sehima, Sorghastrum, Sorghum, Spathia, Thaumastochloa, Themeda, Thelepogon, Vacoparis, Zea
Arundinelleae Arundinella, Garnotia
Paspaleae Otachyriinae Dallwatsonia, Hymenachne, Steinchisma
Paniceae Anthephorinae Digitaria
Cenchrus, Chamaeraphis, Holcolemma, Hygrochloa, Paractaenum, Plagiosetum, Pseudochaetochloa, Pseudoraphis,
Setaria, Spinifex, Stenotaphrum, Uranthoecium, Whiteochloa, Xerochloa, Zulagaea, Zygochloa
Melinideae Eriochloa, Megathyrsus, Melinis, Moorochloa, Thuarea, Urochloa
Boivinellinae Alloteropsis, Cyrtococcum, Echinochloa, Entolasia, Oplismenus, Ottochloa
Neurachninae Ancistrachne, Calytochloa, Cleistochloa, Neurachne, Paraneurachne, Thyridolepis
Panicinae Arthragrostis, Panicum, Yakirra
Incertae Sedis Homopholis, Sacciolepis, Walwhalleya
Cyperochloeae Spartochloea, Cyperochloa