''Balaustion'' is a genus of flowering plants in the myrtle

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 ...

Myrtaceae Myrtaceae (), the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All ...

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 ...

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 ...

Description

Plants in the genus ''Balaustion'' are

glabrous Glabrousness () is the technical term for a lack of hair, down, setae, trichomes, or other such covering. A glabrous surface may be a natural characteristic of all or part of a plant or animal, or be due to loss because of a physical condition, ...

, prostrate to erect shrubs with flowering branchlets with up to six pairs of flowers. The leaves are arranged in opposite pairs and

decussate Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (), ). In Latin anatomical terms, the form is used, e.g. . Similarly, the anatomical term chiasma is named aft ...

, linear to more or less circular with oil

glands A gland is a Cell (biology), cell or an Organ (biology), 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 funct ...

on the lower surface. The flower clusters are borne on a peduncle, each flower

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

or on a long

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 ...

. There are five

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 that are shorter than the petals and five egg-shaped to broadly elliptic petals with 13 to 35

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. The fruit is a slightly kidney-shaped capsule with a rounded outer surface with two equal lateral surfaces and a large inner surface long.

Taxonomy

The genus ''Balaustion'' was first described by

William Jackson Hooker Sir William Jackson Hooker (6 July 178512 August 1865) was an English botany, botanist and botanical illustrator, who became the first director of Kew Gardens, Kew when in 1841 it was recommended to be placed under state ownership as a botan ...

in his ''

Icones Plantarum ''Icones Plantarum'' is an extensive series of published volumes of botanical illustration, initiated by Sir William Jackson Hooker. The Latin name of the work means "Illustrations of Plants". The illustrations are drawn from herbarium specimens of ...

'', and the first species he described (the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

) was '' Balaustion pulcherrimum''.

Species

The following species of ''Balaustion'' are accepted by

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

References

{{Taxonbar, from=Q17443060 Balaustion Myrtales of Australia Endemic flora of Western Australia Taxa named by William Jackson Hooker