''Cyanothamnus coerulescens'', commonly known as blue boronia, is a plant in the citrus

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Rutaceae The Rutaceae () is a family (biology), family, commonly known as the rueRUTACEAE
in Bo ...

and is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to southern

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. It is a small, spindly shrub with

glandular A gland is a cell or an organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also function to remove unwanted substance ...

stems, small, more or less cylindrical leaves and blue to pinkish mauve, four-

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

led flowers. There are two

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

and a third that also occurs in three eastern states.

Description

''Cyanothamnus coerulescens'' is an erect shrub that grows to a height of with branchlets that are warty glandular. The leaves are usually

simple Simple or SIMPLE may refer to: *Simplicity, the state or quality of being simple Arts and entertainment * ''Simple'' (album), by Andy Yorke, 2008, and its title track * "Simple" (Florida Georgia Line song), 2018 * "Simple", a song by John ...

, (sometimes with three lobes), more or less cylindrical in shape to narrow oblong or elliptic, long and wide. The flowers are bright blue, lilac-coloured or white and are arranged singly in leaf

axil A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, fl ...

s or in dense, leafy spikes on the end of the branches. Each flower has a

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

long. The four

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

s are triangular to broadly egg-shaped, long with their bases overlapping. The four

s are more or less egg-shaped with a small, pointed tip, long with their bases overlapping. The eight

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s and the

style Style, or styles may refer to: Film and television * ''Style'' (2001 film), a Hindi film starring Sharman Joshi, Riya Sen, Sahil Khan and Shilpi Mudgal * ''Style'' (2002 film), a Tamil drama film * ''Style'' (2004 film), a Burmese film * '' ...

are slightly hairy. Flowering mostly occurs from August to November and the fruit are long with the petals remaining on the end.

Taxonomy and naming

Blue boronia was first formally described in 1854 by

Ferdinand von Mueller Baron Sir Ferdinand Jacob Heinrich von Mueller, (; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Victoria, Australia ...

who gave it the name ''Boronia coerulescens'' in '' Transactions of the Philosophical Society of Victoria''. In a 2013 paper in the journal ''

Taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

'',

Marco Duretto Marco Duretto (born 1964) is a manager and senior research scientist at the Royal Botanic Gardens Sydney in Australia. His primary research interests are systematics and conservation of Rutaceae, Rubiaceae, Orchidaceae, Stylidiaceae and evoluti ...

and others changed the name to ''Cyanothamnus bussellianus'' on the basis of

cladistic analysis Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

(''coerulescens'') is a

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

word ''caeruleus'' meaning "sky blue" with the ending ''-'' signifying "beginning of" or "becoming". In 2019,

Paul Graham Wilson Paul Graham Wilson (January 1928 – 29 July 2024) was an Australian botanist. As of 1998, Wilson was the most prolific contributor to the journal '' Nuytsia'', contributing to the first issue in 1970 and to the 12th volume in 1998, which was de ...

described three subspecies in the journal ''

Nuytsia ''Nuytsia floribunda'' is a hemiparasitic tree found in Western Australia. The species is known locally as moodjar and, more recently, the Christmas tree or Western Australian Christmas tree. The display of intensely bright flowers during the ...

''. The names have subsequently been changed to reflect the change in the genus name: * ''Cyanothamnus coerulescens'' F.Muell. subsp. ''coerulescens'' (the

autonym Autonym may refer to: * Autonym, the name used by a person to refer to themselves or their language; see Exonym and endonym * Autonym (botany), an automatically created infrageneric or infraspecific name See also * Nominotypical subspecies, in zo ...

) has flowers in leaf axils; * ''Cyanothamnus coerulescens'' subsp. ''spicatus'' ( Paul G.Wilson) Duretto & Heslewood that has flowers in dense, leafy, spike-like

raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...

s; * ''Cyanothamnus coerulescens'' subsp. ''spinescens'' (

Benth. George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...

) Duretto & Heslewood, originally described in 1863 as ''Boronia spinescens'' by

George Bentham George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...

, is a variable subspecies with spreading, often

pungent Pungency ( ) is the taste of food commonly referred to as spiciness, hotness or heat, found in foods such as chili peppers. Highly pungent tastes may be experienced as unpleasant. The term piquancy ( ) is sometimes applied to foods with a lower ...

branchlets and is similar to subspecies ''coerulescens''.

Distribution and habitat

Blue boronia grows in mallee woodland. Subspecies ''coerulescens'' occurs in the

south-west The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A ''compass rose'' is primarily composed of four cardinal directions—north, east, south, and west—each ...

of Western Australia, in

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

Victoria Victoria most commonly refers to: * Queen Victoria (1819–1901), Queen of the United Kingdom and Empress of India * Victoria (state), a state of Australia * Victoria, British Columbia, Canada, a provincial capital * Victoria, Seychelles, the capi ...

and in the far south-west of

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

. 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.

Conservation

All three subspecies of ''C. coerulescens'' are classified as "not threatened" by the Western Australian Government

Department of Parks and Wildlife The Department of Parks and Wildlife (DPaW) was the department of the Government of Western Australia responsible for managing lands described in the ''Conservation and Land Management Act 1984'' and implementing the state's conservation and en ...

References

{{Taxonbar, from=1Q106901925, from2=Q106901947, from3=Q106901937 coerulescens Flora of New South Wales Flora of South Australia Flora of Victoria (state) Flora of Western Australia Plants described in 1854 Taxa named by Ferdinand von Mueller