''Stachystemon'' is a genus of nine species of flowering plants in the family
Picrodendraceae
Picrodendraceae is a family of flowering plants, consisting of 80 speciesStephens, P.F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008. http://www.mobot.org/MOBOT/Research/APweb/ in 25 genera. These are subtropical to Tropics, ...
, 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
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 ...
. Plants in the genus ''Stachystemon'' are
monoecious
Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...
shrubs with
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 ...
, usually thickened leaves, and flowers arranged singly or in small groups in upper leaf axils, male flowers usually with four to six
tepal
A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...
s (sepals and petals together), usually with seven to many
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 female flowers with four or six tepals and two
styles in each flower.
Description
Plants in the genus ''Stachystemon'' are monoecious shrubs with simple, usually thickened,
petiolate leaves with
stipule
In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole (botany), petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part ...
s at the base. The flowers are arranged singly or in small groups in upper leaf axils, often forming clusters on the ends of branchlets with
bract
In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale.
Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...
s at the base. Male flowers are usually arranged on 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
...
, and usually have four to six tepals in two
whorls
A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs).
In nature
File:Photograph and axial plane floral diagram ...
, each male flower with seven to many stamens fused in a central column. Female flowers are more or less
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 ...
, usually with four or six tepals, each flower with two
styles. The fruit is a
capsule containing a single seed with a
caruncle.
Taxonomy
The genus ''Stachystemon'' was first formally described in 1845 by
Jules Émile Planchon
Jules Émile Planchon (21 March 1823 – 1 April 1888) was a French botanist born in Ganges, Hérault. He was a brother of Gustave Planchon who also studied medicinal plants.
Biography
After receiving his Doctorate of Science at the Universit ...
in the ''
London Journal of Botany'', 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 ''
Stachystemon vermicularis''.
The genus name (''Stachystemon'') is derived from Greek words meaning "ear of corn" or "spike", and "thread", referring to the joined stamens.
Species list
The following is a list of species of ''Stachystemon'' accepted by the
Australian Plant Census
The Australian Plant Census (APC) provides an online interface to currently accepted, published, scientific names of the vascular flora of Australia, as one of the output interfaces of the national government Integrated Biodiversity Information Sys ...
as of September 2023:
Distribution
All species of ''Stachystemon'' are endemic to the south-west of Western Australia.
See also
*
Taxonomy of the Picrodendraceae
As the family Picrodendraceae is erected from the bases of subfamily Oldfieldioideae, its taxonomy remains the same:
Tribe Caletieae
There are 4 subtribes and 13 genera:
:Subtribe Dissiliariinae
::''Austrobuxus'' (also ''Buraeavia'', ''Bureau ...
References
{{Taxonbar, from=Q9079538
Malpighiales genera
Endemic flora of Western Australia
Taxa named by Jules Émile Planchon