Editing Epacris impressa (section)

==Taxonomy==
[[File:Epacris impressa pink 6942.jpg|right|thumb|Erect habit, Belgrave South, Victoria]]
The [[type specimen]] of common heath was collected in 1793 by French botanist [[Jacques Labillardière]] in [[Van Diemen's Land]] (now Tasmania) during a voyage with [[Antoine Bruni d'Entrecasteaux]]. Labillardière [[species description|described]] it in his 1805 work ''[[Novae Hollandiae Plantarum Specimen]]'', giving it its current name ''Epacris impressa''.<ref name=APNI23686>{{APNI | name = ''Epacris impressa'' Labill.  | id =23686}}</ref> The Latin [[specific name (botany)|specific epithet]] ''impressa'' (meaning "impressed" or "indented") alludes to the indentations on the floral tube.<ref Name=ANPSA>{{cite web|title=''Epacris impressa''|publisher=Australian Native Plants Society (Australia)|url=http://anpsa.org.au/e-imp.html|access-date=22 April 2010}}</ref> The original mounted specimen is currently held at the [[National Herbarium of Victoria]] at the [[Royal Botanic Gardens, Melbourne]].<ref Name=ABC>{{cite web|title=Floral Emblem ''Epacris impressa''|work=Gardening Australia|publisher=ABC|url=http://www.abc.net.au/gardening/stories/s360511.htm|access-date=22 April 2010|archive-url=https://web.archive.org/web/20080629042618/http://www.abc.net.au/gardening/stories/s360511.htm|archive-date=2008-06-29|url-status=dead}}</ref>

A number of specimens once described as separate species are now regarded as ''Epacris impressa'', with no recognised subspecies.<ref name=APNI23686/> Scottish botanist [[Robert Brown (Scottish botanist from Montrose)|Robert Brown]] described ''Epacris ruscifolia'' in his 1810 work ''[[Prodromus Florae Novae Hollandiae et Insulae Van Diemen]]'' alongside ''E. impressa''.<ref name="R.Br. 1810">{{cite book | author = Brown, Robert | year = 1810 | title = Prodromus Florae Novae Hollandiae et Insulae Van Diemen |pages = 406–08 | location = London, United Kingdom | publisher = Richard Taylor and Company | author-link = Robert Brown (Scottish botanist from Montrose) | url=https://www.biodiversitylibrary.org/page/2938981}}</ref><ref name=APNI25612>{{APNI | name = ''Epacris ruscifolia'' R.Br.  | id =25612|access-date=5 June 2014}}</ref> [[John Lindley]] described ''Epacris tomentosa'' from plant specimens collected during the third expedition of [[Thomas Mitchell (explorer)|Thomas Mitchell]] in 1838. Upon encountering ''Epacris impressa'' on [[Mount William (Mount Duwil)|Mount William]] in the Grampians, Mitchell remarked that it was "A most beautiful downy-leaved Epacris with large, curved, purple flowers, allied to ''[[Epacris longiflora|E. grandiflora]]''{{refn|Mitchell here makes a comparison to ''Epacris grandiflora'' Willd., a synonym of ''[[Epacris longiflora]]'', not to be confused with ''Epacris impressa'' var. ''grandiflora'' Benth.|group="nb"}} but much handsomer".<ref>{{cite book| author=Lindley, John|editor=Mitchell, Thomas L. |year=1839 |title= Three Expeditions into the interior of Eastern Australia |publisher=T. & W. Boone|volume= 2 |page=177|url=https://books.google.com/books?id=vqBaDgiAIDAC&pg=PA177}}</ref> Dr [[Robert Graham (botanist)|Robert Graham]] described ''Epacris ceriflora'' (which he spelt ''ceraeflora'') from plants cultivated at the Edinburgh Botanic Gardens in 1832. The seed had come from Tasmania, the resulting progeny flowering over April and May 1832.<ref>{{cite journal|last=Graham|first=Robert|date=1832|title=Dr Graham's Description of New or Rare Plants |journal=Edinburgh New Philosophical Journal|volume=13|pages=167–73 [168]|url=https://www.biodiversitylibrary.org/page/25429056}}</ref>  A year later, he described ''E. nivalis'', which he called an "exceedingly beautiful species", from specimens growing in [[Loddiges]] nursery. He also noted a form with long corollas that had been called  ''E. variabilis'' that was in cultivation at the time, and noted it was difficult to describe the precise characteristics that distinguished ''E. ceraeflora'', ''E. nivalis'', ''E. variabilis'' and ''E. impressa''.<ref>{{cite journal|last=Graham|first=Robert|date=1833|title=Dr Graham's Description of New or Rare Plants |journal=Edinburgh New Philosophical Journal|volume=15|pages=181–84 [183]|url=https://www.biodiversitylibrary.org/page/2498656}}</ref>

In his landmark ''[[Flora Australiensis]]'' (1869), [[George Bentham]] argued that several previously described species were in fact a single species – ''E. impressa'',<ref name="Bentham 1869">{{cite encyclopedia | author = Bentham, George | year = 1869 | title = ''Epacris impressa'' | encyclopedia = [[Wikisource:Flora Australiensis|Flora Australiensis]] | volume = 4: Stylidiaeeae to Pedalineae | pages = 235 | location = London, United Kingdom | publisher = L. Reeve & Co. | author-link = George Bentham| url=https://www.biodiversitylibrary.org/page/11266456 }}</ref> uniting ''E. variabilis'', a short red-flowered ''E. campanulata'', ''E. ruscifolia'', which had narrow leaves and long flowers, the white-flowered ''E. nivalis'', and short white-flowered ''E. ceraeflora''. He re-classified as a separate species – ''[[Epacris reclinata|E. reclinata]]'' – several plants that [[Allan Cunningham (botanist)|Allan Cunningham]] had collected in the [[Blue Mountains (New South Wales)|Blue Mountains]] and classified as ''E. impressa''.<ref name="Bentham 1869"/>

In the same work,  Bentham named and described two naturally occurring varieties, ''Epacris impressa'' var. ''grandiflora'' and ''E. impressa'' var. ''ovata''.<ref name=StaceI/> Plant specimens designated as ''grandiflora'' had been collected in the [[Wimmera]], the [[Grampians National Park|Grampians]] (including those previously designated as ''E. tomentosa'') and at [[Stawell, Victoria|Stawell]] in Victoria. Those classified as ''ovata'' were collected at [[Twofold Bay]] and [[Mount Imlay]] in southeastern New South Wales as well as [[Cape Grim|Woolnorth]] and [[Rocky Cape National Park|Rocky Cape]] in northern Tasmania.<ref name=APNI23924/><ref name=APNI24101>{{APNI|name=''Epacris impressa'' var. ''ovata'' Benth.|id=24101|access-date=6 June 2014}}</ref> Bentham noted that, although variable, all forms had "five impressed cavities outside, alternating with the stamens immediately above the ovary."<ref name="Bentham 1869"/>

In his 1972 publication ''A Handbook to Plants in Victoria'', Australian botanist [[James Hamlyn Willis|Jim Willis]] expressed his view that dividing the species into subspecies was not feasible given that common heath is highly variable in flower colour and leaf shape, though he conceded the Grampians race ''grandiflora'' might be distinctive based on its larger [[Catacorolla|corolla]]s and coarser and hairier foliage.<ref name=StaceI/> Currently, both ''grandiflora'' and ''ovata'' are regarded as synonyms of ''Epacris impressa'' rather than being classified as distinct varieties.<ref name=APNI23924/><ref name=APNI24101/> The plant populations that best fit Bentham's original description of ''grandiflora'', also known as Grampians heath, occur naturally on [[sandstone]] at locations including Mount Zero, Mount Stapylton and the [[Black Range State Park|Black Range]].<ref name="Cochrane 1980"/><ref name=RBG/> Other nearby populations are regarded as having intermediate characteristics, including those in the Victoria Range and [[Mount Arapiles]].<ref name=RBG>{{cite web|title=''Epacris impressa''|work=Flora of Victoria Knowledge Base|publisher=Royal Botanic Gardens Melbourne|url=http://www.rbg.vic.gov.au/dbpages/dev/vicflora/index.php/viclist/name/835|archive-url=https://web.archive.org/web/20140606224112/http://www.rbg.vic.gov.au/dbpages/dev/vicflora/index.php/viclist/name/835|archive-date=2014-06-06|access-date=6 June 2014}}</ref> Although not recognised in the [[Australian Plant Census]], the variety is noted as "rare" on the list of ''Advisory List of Rare or Threatened Plants in Victoria'' issued by the [[Department of Environment and Primary Industries]].<ref name=APNI23924/><ref name=DEPI>{{cite web|title=Threatened species advisory lists|publisher=Department of Environment and Primary Industries|url=http://www.depi.vic.gov.au/environment-and-wildlife/threatened-species-and-communities/threatened-species-advisory-lists|access-date=10 June 2014|archive-date=11 March 2014|archive-url=https://web.archive.org/web/20140311150608/http://www.depi.vic.gov.au/environment-and-wildlife/threatened-species-and-communities/threatened-species-advisory-lists|url-status=dead}}</ref>

===Variation in flower colour and length===
{{Multiple image
| align     = right
| direction = vertical
| header    = Forms of ''E. impressa''
| width     =
| image1    = Epacris impressa white 3984.jpg
| alt1      = white-flowered shrub
| caption1  = White-flowering form, southern Victoria
| image2    = Common Heath.jpg
| alt2      = pink-flowered shrub
| caption2  = Pink-flowering form, Tasmania
| image3    = Epacris impressa red 5755.jpg
| alt3      = red-flowered shrub
| caption3  = Scarlet-flowering form, Wilsons Promontory
}}

In 1977 Helen Stace and Yvonne Fripp from [[La Trobe University]] studied 195 populations of ''Epacris impressa'' in Victoria, South Australia and Tasmania and found that 120 consisted of mixed stands of two or more [[Race (biology)|races]] while 75 populations were of one race only. They identified four races based on the following corolla characteristics:<ref name=StaceI/>

*white-flowered with a markedly shortened corolla that is {{convert|9-12|mm|in|frac=8|abbr=on}} long and red-purple anthers,<ref name=StaceI/> usually found in sites with greater sun exposure.<ref name=StaceII/> Occurring throughout the species range,<ref name=StaceI/> this form is the most widely distributed.<ref name=StaceII/> 
*pink-flowered, with a longer corolla that is {{convert|12-19|mm|in|frac=8|abbr=on}} long and cream-white anthers, in more shaded sites.<ref name=StaceII/> This form occurs throughout the species range.<ref name=StaceI/> Field work in Victoria and Tasmania found that pink-flowered plants in mixed populations often have pink or red anthers.<ref name=StaceIII>{{cite journal |last1=Stace |first1=Helen M. |last2=Fripp |first2=Yvonne J. |year=1977 |title=Raciation in ''Epacris impressa''. III.Polymorphic Populations  |journal= [[Australian Journal of Botany]]|volume=25 |pages= 325–36|doi= 10.1071/BT9770325 }}</ref>
*long scarlet race, with orange-red flowers and corolla {{convert|15-19|mm|in|frac=8|abbr=on}} long and cream-white anthers. Those from the granitic mountains of [[Wilsons Promontory]] and near [[W Tree, Victoria|W Tree]] in East Gippsland in Victoria flower between April and November. Other localities where this race has been recorded include the Howe Ranges and [[Clyde Mountain]] in New South Wales.<ref name=StaceI/>
*broad pink or white, the ''grandiflora'' race from the [[Grampians National Park|Grampians]] and [[Mount Arapiles]] in Victoria. Plants of this race are taller, often reaching {{convert|2|m|ftin}} in height. White or pink colour bear no relation to corolla length. Plants from Mount Arapiles are always pink-flowered.<ref name=StaceI/>
 
The long-pink and short-white races frequently occur in close proximity to each other; in these mixed populations the former tends to flower in winter and the latter in spring.<ref name=StaceI>{{cite journal |last1=Stace |first1=Helen M. |last2=Fripp |first2=Yvonne J. |year=1977 |title=Raciation in ''Epacris impressa''. I. Corolla Colour and Corolla Length.  |journal= [[Australian Journal of Botany]]|volume=25 |issue= 3|pages= 299–314|doi= 10.1071/BT9770299}}</ref><ref name=StaceII>{{cite journal |last1=Stace |first1=Helen M. |last2=Fripp |first2=Yvonne J. |year=1977 |title=Raciation in ''Epacris impressa''. II. Habitat Differences and Flowering Times.  |journal= Australian Journal of Botany|volume=25 |issue= 3|pages= 315–23|doi= 10.1071/BT9770315}}</ref> The question has been raised whether these different forms are becoming incompatible. However, controlled cross-pollination between plants with short and long corollas showed that there was no incompatibility between them.<ref name=Obrien89>{{cite journal | title= The Breeding Biology of ''Epacris impressa''. Is This Species Heterostylous? |author1=O'Brien, Susan P. |author2=Calder, D.M. | journal= Australian Journal of Botany |volume=37|issue=1|pages=43–54 |year= 1989 |doi=10.1071/BT9890043}}</ref>

Pink-flowering populations have a relatively distinct [[genome|genetic makeup]], whereas red or white flowering populations have more evident sharing of genetic traits.<ref name=Conomikes>{{cite report|author=Conomikes, Melanie|title=''Epacris impressa'' Labil: Inoculation of cuttings with ericoid mycorrhizal fungus and DNA fingerprinting of floral races – Final Report to the Australian Flora Foundation|date=February 2008|url=http://www.aff.org.au/Conomikes_Epacris_final.pdf|access-date=22 April 2010|url-status=dead|archive-url=https://web.archive.org/web/20090912184337/http://www.aff.org.au/Conomikes_Epacris_final.pdf|archive-date=12 September 2009}}</ref> Research based on [[DNA profiling]] has revealed substantial genetic diversity within and between flower colour races and site populations. This has implications for vegetation projects in that [[provenance]] material needs to be collected from a wide geographic area to maintain this diversity.<ref name=Conomikes2012>{{Cite journal | last1= Conomikes | first1= Melanie | last2= Moore | first2= Gregory M. | last3= McLean | first3= Cassandra | year= 2012 | title= Genetic Analysis Reveals a Wide Regional Provenance Distribution for ''Epacris impressa'' | journal= Muelleria | volume= 30 | issue= 2 | pages= 175–82 | doi= 10.5962/p.292247 | s2cid= 251006909 | url= http://www.rbg.vic.gov.au/documents/Muelleria_30%282%29%2C_Conomikes_High_Res.pdf | access-date= 1 June 2014}}</ref>