''Boronia'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of about 160 species of flowering plants 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 ...

. Most are

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 ...

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 ...

with a few species in

New Caledonia New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...

, which were previously placed in the genus ''Boronella''. They occur in all Australian states but the genus is under review and a number of species are yet to be described or have the description published. Boronias are similar to familiar plants in the genera ''

Zieria ''Zieria'' is a genus of plants in the family, Rutaceae. About sixty species have been formally described, all of which are endemic to Australia except for one species which is found in New Caledonia. They occur in all Australian states except ...

'', ''

Eriostemon ''Eriostemon'' is a genus of flowering plants of the family Rutaceae. It is native to eastern Australia and includes just two species, '' E. australasius'' and '' E. banksii''. ''Eriostemon australasius'', commonly known as pink wax flower, oc ...

'' and '' Correa'' but can be distinguished from them by the number of

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 ...

s or

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. Some species have a distinctive fragrance and are popular garden plants.

Description

Plants in the genus ''Boronia'' are nearly always shrubs although a very small number occur as

herbs Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnish (food), garnishing food, for medicinal purposes, or for fragrances. Culinary use typi ...

or as small trees. The leaves are usually arranged in opposite pairs and may be simple leaves or

compound leaves 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 ...

with up to nineteen or more leaflets, in either a

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

bipinnate The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets ...

arrangement. The flowers are arranged in groups in the 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 on the ends of the branches and have both male and female parts. There are usually four separate

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, usually four separate

s and generally eight

s. (In ''Zieria'' there are only four stamens, ''Eriostemon'' species have five petals and in ''Correa'' the petals are joined to form a bell-shaped tube.) There are four

carpels Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ...

with their styles fused and there are two

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the sporangium, megasporangium), ...

s in each carpel. Boronia algida

Taxonomy and naming

The genus ''Boronia'' was first formally described in 1798 by James Edward Smith and the description was published in ''Tracts Relating to Natural History''. The name ''Boronia'' honours Francesco Borone (1769 - 1794), Italian naturalist and plant collector, who assisted

John Sibthorp John Sibthorp (28 October 1758 – 8 February 1796) was an English botanist. Education Sibthorp graduated from the University of Oxford in 1777 where he was an undergraduate student at Lincoln College, Oxford. He subsequently studied medi ...

in Greece and Turkey,

Adam Afzelius Adam Afzelius (8 October 175020 January 1837) was a Swedish botanist and an apostle of Carl Linnaeus. Afzelius was born at Larv in Västergötland in 1750. He was appointed teacher of oriental languages at Uppsala University in 1777, and in 1785 ...

in Sierra Leone and James Edward Smith during his European tour in 1787.

Boronia ''Boronia'' is a genus of about 160 species of flowering plants in the citrus family Rutaceae. Most are endemic to Australia with a few species in New Caledonia, which were previously placed in the genus ''Boronella''. They occur in all Australi ...

, an outer suburb of

Melbourne Melbourne ( , ; Boonwurrung language, Boonwurrung/ or ) is the List of Australian capital cities, capital and List of cities in Australia by population, most populous city of the States and territories of Australia, Australian state of Victori ...

was named after a boronia found growing in the area.

Distribution and habitat

Boronias are found in all states and mainland territories of Australia and generally grow in open forests or woodlands, only rarely in rainforests or arid areas.

Use in horticulture

Boronias, especially '' B. megastigma'', are known for their perfumed flowers. Most are regarded as desirable specimens in the garden, however, many are difficult to grow in cultivation. All species require excellent drainage and part shade.

References

{{Authority control Zanthoxyloideae genera

Description

Taxonomy and naming

Distribution and habitat

Use in horticulture

See also

References