Stylidium perpusillum, the tiny triggerplant, 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 occurs in south west

Southwest Australia

Southwest Australia is a biodiversity hotspot that includes the Mediterranean forests, woodlands, and scrub ecoregions of Western Australia. The region has a wet-winter, dry-summer Mediterranean climate, one of five such regions in the world...

 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...

.

It is an ephemeral

Ephemeral Plant

An ephemeral plant is one marked by short life cycles, usually six to eight weeks. The word ephemeral means transitory or quickly fading. In regards to plants, it refers to several distinct growth strategies...

 annual

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 1.5 to 4 cm tall. It bears white flowers with undivided posterior corolla petals that bloom from September to November in its native range. Its habitat has been reported as being sand to clay soils in winter-wet depressions near granitic rocks. S. perpusillum is a tropical species endemic to southwestern, Western Australia and is considered to be the smallest species in the genus Stylidium. Johannes Mildbraed

Johannes Mildbraed

Gottfried Wilhelm Johannes Mildbraed was a German botanist that specialized in mosses, ferns, and various spermatophytes. He is well-known for authoring the most current monograph and taxonomic treatment of the family Stylidiaceae in 1908 as part of the unfinished Das Pflanzenreich series. The...

, in his 1908 monograph on the family, described S. perpusillum as also being present in Victoria

Victoria (Australia)

Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....

 and Tasmania

Tasmania

Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

, but all other collections since have only been in Western Australia.