Cyanothamnus coerulescens
{{short description|Species of plant}}
{{Speciesbox
|name = Blue boronia
|image = Boronia coerulescens.jpg
|image_caption = Boronia coerulescens in the Little Desert National Park
|taxon = Cyanothamnus coerulescens
|authority = (F.Muell.) Duretto & Heslewood{{cite web |title=Cyanothamnus coerulescens |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77211024-1 |publisher=Plants of the World Online |access-date=21 September 2021}}
|range_map = Boronia coerulescensDistMap24.png
|range_map_caption = Occurrence data from Australasian Virtual Herbarium
}}
Cyanothamnus coerulescens, commonly known as blue boronia, is a plant in the citrus family, Rutaceae and is endemic to southern Australia. It is a small, spindly shrub with glandular stems, small, more or less cylindrical leaves and blue to pinkish mauve, four-petalled flowers. There are two subspecies endemic to Western Australia and a third that also occurs in three eastern states.
Description
Cyanothamnus coerulescens is an erect shrub that grows to a height of {{convert|0.2-0.6|m|ft|sigfig=1|abbr=on}} with branchlets that are warty glandular. The leaves are usually simple, (sometimes with three lobes), more or less cylindrical in shape to narrow oblong or elliptic, {{convert|5-10|mm|in|sigfig=2|abbr=on}} long and {{convert|0.5-1.5|mm|in|sigfig=2|abbr=on}} wide. The flowers are bright blue, lilac-coloured or white and are arranged singly in leaf axils or in dense, leafy spikes on the end of the branches. Each flower has a pedicel {{convert|2-5|mm|in|sigfig=1|abbr=on}} long. The four sepals are triangular to broadly egg-shaped, {{convert|1.5-7|mm|in|sigfig=1|abbr=on}} long with their bases overlapping. The four petals are more or less egg-shaped with a small, pointed tip, {{convert|3-9|mm|in|sigfig=1|abbr=on}} long with their bases overlapping. The eight stamens and the style are slightly hairy. Flowering mostly occurs from August to November and the fruit are {{convert|3-4|mm|in|sigfig=2|abbr=on}} long with the petals remaining on the end.{{cite web |last1=Duretto |first1=Marco F. |title=Boronia coerulescens subsp. coerulescens |url=https://vicflora.rbg.vic.gov.au/flora/taxon/704096f2-2db9-44ed-873a-de2e7413a9a4 |publisher=Royal Botanic Gardens Victoria |accessdate=27 January 2019}}{{cite web |last1=Weston |first1=Peter H. |last2=Duretto |first2=Marco F. |title=Boronia coerulescens subsp. coerulescens|url=http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=in&name=Boronia~coerulescens+subsp.~coerulescens|publisher=Royal Botanic Garden Sydney |accessdate=27 January 2019}}{{cite journal |last1=Wilson |first1=Paul G. |title=Taxonomic notes on the family Rutaceae, principally of Western Australia |journal=Nuytsia |date=1971 |volume=2 |issue=1 |pages=200–201 |url=https://www.biodiversitylibrary.org/item/223158#page/46/mode/1up |accessdate=27 January 2019}}{{cite web |title=Boronia coerulescens |url=http://www.flora.sa.gov.au/cgi-bin/speciesfacts_display.cgi?form=speciesfacts&family=&genus=Boronia&species=coerulescens&iname=&submit=Display |publisher=State Herbarium of South Australia |accessdate=28 January 2019}}
Taxonomy and naming
Blue boronia was first formally described in 1854 by Ferdinand von Mueller who gave it the name Boronia coerulescens in Transactions of the Philosophical Society of Victoria.{{cite web|title=Boronia coerulescens|url= https://id.biodiversity.org.au/instance/apni/464078|publisher=APNI|accessdate=27 January 2019}}{{cite journal |last1=von Mueller |first1=Ferdinand |title=Definition of rare or hitherto undescribed Australian plants, chiefly collected within the boundaries of the colony of Victoria |journal=Transactions of the Philosophical Society of Victoria |date=1854 |volume=1 |page=11 |url=https://www.biodiversitylibrary.org/item/175165#page/31/mode/1up |accessdate=27 January 2019}} In a 2013 paper in the journal Taxon, Marco Duretto and others changed the name to Cyanothamnus bussellianus on the basis of cladistic analysis.{{cite journal |last1=Duretto |first1=Marco F. |last2=Heslewood |first2=Margaret M. |last3=Bayly |first3=Michael J. |title=Boronia (Rutaceae) is polyphyletic: Reinstating Cyanothamnus and the problems associated with inappropriately defined outgroups |journal=Taxon |date=2020 |volume=69 |issue=3 |pages=481–499 |doi=10.1002/tax.12242|s2cid=225836058 }} The specific epithet (coerulescens) is a Latin word caeruleus meaning "sky blue"{{cite book|last1=Brown|first1=Roland Wilbur|title=The Composition of Scientific Words|date=1956|publisher=Smithsonian Institution Press|location=Washington, D.C.}}{{rp|152}} with the ending -{{lang|la|escens}} signifying "beginning of" or "becoming".{{rp|135}}
In 2019, Paul Graham Wilson described three subspecies in the journal Nuytsia. The names have subsequently been changed to reflect the change in the genus name:
- Cyanothamnus coerulescens F.Muell. subsp. coerulescens (the autonym) has flowers in leaf axils;
- Cyanothamnus coerulescens subsp. spicatus (Paul G.Wilson) Duretto & Heslewood that has flowers in dense, leafy, spike-like racemes;{{cite web |title=Cyanothamnus coerulescens subsp. spicatus |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77211028-1 |publisher=Plants of the World Online |access-date=21 September 2021}}
- Cyanothamnus coerulescens subsp. spinescens (Benth.) Duretto & Heslewood, originally described in 1863 as Boronia spinescens by George Bentham,{{cite web |title=Cyanothamnus coerulescens subsp. spinescens |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77211029-1 |publisher=Plants of the World Online |access-date=21 September 2021}}{{cite book |last1=Bentham |first1=George |title=Flora Australiensis |volume=v. 1 |date=1863 |publisher=Lovell, Reeve & Co. |location=London |pages=319–320 |url=https://www.biodiversitylibrary.org/item/3669#page/377/mode/1up |accessdate=28 January 2019}} is a variable subspecies with spreading, often pungent branchlets and is similar to subspecies coerulescens.
Distribution and habitat
Blue boronia grows in mallee woodland. Subspecies coerulescens occurs in the south-west of Western Australia, in South Australia, Victoria and in the far south-west of New South Wales. Subspecies spicata occurs in Western Australia between Wubin and Muntadgin and spinescens is found in similar areas to subspecies coerulescens but only in Western Australia.{{FloraBase|name=Cyanothamnus coerulescens|id=50110}}
Conservation
All three subspecies of C. coerulescens are classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.{{FloraBase|name=Cyanothamnus coerulescens subsp. coerulescens|id=50112}}{{FloraBase|name=Cyanothamnus coerulescens subsp. spicatus|id=50113}}{{FloraBase|name=Cyanothamnus coerulescens subsp. spinescens|id=50111}}
References
{{Reflist|30em}}
{{Taxonbar|from=1Q106901925|from2=Q106901947|from3=Q106901937}}
Category:Flora of New South Wales
Category:Flora of South Australia
Category:Flora of Victoria (state)
Category:Flora of Western Australia