Stylidium darwinii is a small, erect 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...

 plant 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...

). It grows up to 4.5 cm (1.8 in) tall. Elliptic-oblong

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 obovate to orbicular leaves are scattered and alternate along the simple, glabrous stem. The leaves are generally 2-3 mm long and 1.5-1.8 mm wide. 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 produce many violet-pink flowers, which flower from September to November. Stylidium darwinii is only known from Anshi National Park

Anshi National Park

Anshi National Park is located in Uttara Kannada district, in the Indian state of Karnataka, bordering the state of Goa...

 in the Uttara Kannada district of Karnataka

Karnataka

Karnataka , the land of the Kannadigas, is a state in South West India. It was created on 1 November 1956, with the passing of the States Reorganisation Act and this day is annually celebrated as Karnataka Rajyotsava...

, India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. Its habitat is recorded as being moist gravelly soils on the outskirts of evergreen forests near roadsides at an altitude of 530 m (1,739 ft). It can be found in association with several carnivorous plant

Carnivorous plant

Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...

 species, including Drosera burmannii

Drosera burmannii

Drosera burmannii, the tropical sundew, is a small, compact species in the carnivorous plant genus Drosera. It normally spans only in diameter. It is one of the fastest trapping sundews as well, and its leaves can curl around an insect in only a few seconds, compared to the minutes or hours it...

, Drosera indica

Drosera indica

Drosera indica is an insectivorous plant, a sundew native to tropical countries throughout the world, from Australia and Asia to Africa, but absent from the neotropics. Together with D. hartmeyerorum it makes up the section Arachnopus....

, and Utricularia caerulea

Utricularia caerulea

Utricularia caerulea, the blue bladderwort, is a very small to medium-sized carnivorous plant that belongs to the genus Utricularia. U. caerulea spans a wide native range, including areas in tropical Africa, Asia, and Australia...

. The specific epithet darwinii was given to this species in honor of Charles Darwin

Charles Darwin

Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

.

This species was first located in 2007 as part of a floristic survey of Anshi National Park and was first formally described by Sachin A. Punekar and P. Lakshminarasimhan in 2010. It was placed in subgenus Andersonia

Stylidium subg. Andersonia

Andersonia is a subgenus of Stylidium that is characterized by a linear hypanthium, recurved mature capsule walls, an erect and persistent septum, and many seeds...

, but the authors did not identify a section. They did, however, note that S. darwinii is closely allied with S. kunthii

Stylidium kunthii

Stylidium kunthii is a dicotyledonous plant that belongs to the genus Stylidium and is one of the few species in the genus that is not native to Australia. It is an erect annual plant that grows from 8 to 20 cm tall. Obovate, orbicular, or obleanceolate leaves, about 5-15 per plant, form...

, S. inconspicuum

Stylidium inconspicuum

Stylidium inconspicuum is a dicotyledonous plant that belongs to the genus Stylidium . It is an annual plant that grows from 5 to 20 cm tall. Obovate or elliptical leaves, about 5-30 per plant, are scattered along the elongate, glabrous stem. The leaves are generally 4-8 mm long and...

, and S. tenellum

Stylidium tenellum

Stylidium tenellum is a dicotyledonous plant that belongs to the genus Stylidium . It is an annual plant that grows from 5 to 27 cm tall. The obovate or elliptical leaves, about 6-14 per plant, are scattered along the elongate, glabrous stem and are generally 3.5-8.5 mm long and...

.