Stylidium inaequipetalum, the Ayers Rock triggerplant, is a small herbaceous perennial plant

Perennial plant

A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

 in the genus Stylidium. It grows from 7 to 40 cm (2.8 to 15.7 in) tall. Oblanceolate

Leaf shape

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

 leaves, about 20-100 per plant, form a basal rosette

Rosette (botany)

In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...

 with stems

Plant stem

A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...

 absent. The leaves are generally 15-81 mm long and 2-8 mm wide. This species produces 1-11 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....

 per plant. 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 are 7-40 cm long and produce pink flowers with petals all free and blooms almost year-round in their native range. S. inaequipetalum is endemic to the southwestern 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...

 and 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...

. Its typical habitat has been reported as sandy soils on sheltered creekbanks or in between rocks. S. inaequipetalum is most closely related to S. floribundum

Stylidium floribundum

Stylidium floribundum is a dicotyledonous plant that belongs to the genus Stylidium . It is an herbaceous annual plant that grows from 7 to 18 cm tall. Oblanceolate or obovate leaves, about 6-30 per plant, form a basal rosette with stems absent. The leaves are generally 8–48 mm long and...

, though it is also closely allied with S. debile

Stylidium debile

Stylidium debile, commonly known as the frail triggerplant, is a carnivorous, dicotyledonous plant that belongs to the genus Stylidium . S. debile is endemic to coastal areas in Queensland and New South Wales, Australia....

.

It was first described by John McConnell Black

John McConnell Black

John McConnell Black was a Scottish botanist who emigrated to Australia in 1877 and eventually documented and illustrated thousands of flora in South Australia in the early 20th century. His publications assisted many botanists and scientists in the decades that followed...

in a 1938 issue of the Transactions of the Royal Society of South Australia.