Stylidium pachyrrhizum is a dicotyledon

Dicotyledon

The dicotyledons, also known as dicots, are a group of flowering plants whose seed typically has two embryonic leaves or cotyledons. There are around 199,350 species within this group...

ous plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

 that belongs to the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Stylidium (family Stylidiaceae

Stylidiaceae

The family Stylidiaceae is a taxon of dicotyledonous flowering plants. It consists of five genera with over 240 species, most of which are endemic to Australia and New Zealand. Members of Stylidiaceae are typically grass-like herbs or small shrubs and can be perennials or annuals...

) that was described by Ferdinand von Mueller

Ferdinand von Mueller

Baron Sir Ferdinand Jacob Heinrich von Mueller, KCMG was a German-Australian physician, geographer, and most notably, a botanist.-Early life:...

 in 1859. It is an erect annual plant

Annual plant

An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...

 that grows from 15 to 40 cm tall. Obovate

Leaf shape

In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...

 or oblanceolate leaves, about 5-30 per plant, are scattered along the stems. The leaves are generally 13-100 mm long and 3.5–24 mm wide. This species generally has one to six scapes

Scape (botany)

In botany, scapes are leafless flowering stems that rise from the ground. Scapes can have a single flower or many flowers, depending on the species....

 and cymose inflorescence

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

s that are 13–33 cm long. Flowers are white or pink. S. pachyrrhizums distribution ranges from western Kimberley in Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 and extends to Groote Eylandt

Groote Eylandt

Groote Eylandt is the largest island in the Gulf of Carpentaria in northeastern Australia. It is the homeland of, and is owned by, the Anindilyakwa people who speak the isolated Anindilyakwa language)....

 off the east coast of the Northern Territory

Northern Territory

The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...

. Its typical habitats are swamp margins or seepage areas near sandy or rocky creeks. It flowers in the southern hemisphere

Southern Hemisphere

The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

 from March to June. S. pachyrrhizum is most closely related to S. schizanthum

Stylidium schizanthum

Stylidium schizanthum is a dicotyledonous plant that belongs to the genus Stylidium that was described by Ferdinand von Mueller in 1859. It is an erect annual plant that grows from 9 to 30 cm tall. Obovate, orbicular, or oblanceolate leaves, about 3-13 per plant, form basal rosettes. The...

 and S. stenophyllum

Stylidium stenophyllum

Stylidium stenophyllum is a dicotyledonous plant that belongs to the genus Stylidium that was described by A.R. Bean in 2000. It is an erect annual plant that grows from 30 to 40 cm tall. Linear leaves, about 7-25 per plant, are scattered along the stems. The leaves are generally...

and some specimens are hard to differentiate between S. pachyrrhizum and S. schizanthum.