''Boronia citriodora'', commonly known as lemon-scented boronia, lemon plant or lemon thyme, is a woody shrub that is

endemic Endemism is the state of a species being found 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 found else ...

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

. It has

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 in ...

leaves and white to pink flowers that are arranged singly or in groups of up to seven, in the leaf axils or on the ends of the branches. Boronia citriodora 1

Description

''Boronia citriodora'' is a woody shrub that is sometimes prostrate, otherwise erect and growing to a height of . It has pinnate leaves that are long and wide in outline with between three and nine leaflets, on a petiole long. The end leaflet is narrow elliptic to narrow lance-shaped, long and wide. The side leaflets are similar but longer. The flowers are white to pink and are arranged singly or in groups of up to seven in leaf axils or on the ends of branches on a stalk 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 The term ''sepalum'' was coine ...

s are triangular, long and wide. The four petals are long and the eight stamens have a few short hairs. Flowering occurs from November to February and the mature fruit are smooth, long and wide.

Taxonomy and naming

''Boronia citriodora'' was first formally described in 1855 by

Joseph Dalton Hooker Sir Joseph Dalton Hooker (30 June 1817 – 10 December 1911) was a British botanist and explorer in the 19th century. He was a founder of geographical botany and Charles Darwin's closest friend. For twenty years he served as director of ...

from an unpublished description by Ronald Campbell Gunn and the description was published in '' The botany of the Antarctic voyage of H.M. Discovery ships Erebus and Terror''. The name is derived from the characteristic lemon scent of the foliage. Hooker noted that the plant has a "strong and delicious smell of lemons" and that the species was called the 'lemon-plant' by early Tasmanian colonists. In 2003, Marco Duretto described three subspecies: * ''Boronia citriodora'' subsp. ''citriodora'' that has smooth sepals and leaves less than long; * ''Boronia citriodora'' subsp. ''orientalis'' that has hairy sepals; * ''Boronia citriodora'' subsp. ''paulwilsonii'' that has smooth sepals and at least some leaves more than long.

Distribution and habitat

Lemon-scented boronia grows in heath, woodland and near rainforest, often in rocky places. * Subspecies ''citriodora'' only grows on the Central Highlands of Tasmania, at altitudes above with disjunct populations further south, including on Mount Field. UTas.edu.au: Boronia citriodora
/ref> * Subspecies ''orientalis'' is only known from

Ben Lomond Ben Lomond (Scottish Gaelic: Beinn Laomainn, 'Beacon Mountain'), , is a mountain in the Scottish Highlands. Situated on the eastern shore of Loch Lomond, it is the most southerly of the Munros. Ben Lomond lies within the Ben Lomond National Me ...

and Mount Barrow; * Subspecies ''paulwilsonii'' is only known from the south-west of Tasmania, south from

Macquarie Harbour Macquarie Harbour is a shallow fjord in the West Coast region of Tasmania, Australia. It is approximately , and has an average depth of , with deeper places up to . It is navigable by shallow-draft vessels. The main channel is kept clear by th ...

and west from Mount Shea.

Use in horticulture

''Boronia citriodora'' is cultivated as an

ornamental plant Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...

for use in gardens. It tolerates sun, shade, wind, heavy frost; and dry, sandy or waterlogged soils.

References

{{Taxonbar, from=Q2911251 citriodora Endemic flora of Tasmania Garden plants of Australia Plants described in 1855 Taxa named by Joseph Dalton Hooker