Stylidium is a genus of dicotyledonous plants that belong to the family Stylidiaceae. The genus name Stylidium is derived from the Greek στύλος or stylos, which refers to the distinctive reproductive structure that its flowers possess. Pollination is achieved through the use of the sensitive "trigger", which comprises the male and female reproductive organs fused into a floral column that snaps forward quickly in response to touch, harmlessly covering the insect in pollen. Most of the approximately 300 species are only found in Australia, making it the fifth largest genus in that country. Triggerplants are considered to be protocarnivorous or carnivorous because the glandular trichomes that cover the scape and flower can trap, kill, and digest small insects with protease enzymes produced by the plant. Recent research has raised questions as to the status of protocarnivory within Stylidium.
Stylidium adnatum is a dicotyledonous plant that belongs to the genus Stylidium. S. adnatum is endemic to Australia and is found primarily in the southwest region of Western Australia.
Stylidium hispidum, the white butterfly triggerplant, is a dicotyledonous plant that belongs to the genus Stylidium. S. hispidum is endemic to Australia and is found primarily in southwest Western Australia near Perth. This species is a basally rosetted triggerplant with greyish, linear leaves growing up to three cm. The scape is reddish, from six to thirty cm tall ending in a somewhat branched raceme giving rise to white or cream-colored flowers, which have red spots near the throat of the flower. The primary habitat for S. hispidum includes jarrah forests, gravelly loams, and light sandy soils.
Stylidium turbinatum is a dicotyledonous plant that belongs to the genus Stylidium. S. turbinatum is endemic to Australia and is found in the northern part of Western Australia in the Kimberley region and near Darwin in the Northern Territory. This species is an erect annual herb that stands 6–15 cm tall. A 2–5 cm long stem bearing scattered leaves terminate in a tuft of 1–2 cm long upper leaves. Several scapes appear from these terminal tufts. The inflorescence is a raceme, which produces pink flowers whose petals are vertically paired. The hypanthium of this species is turbinate and is one of the distinguishing characteristics used to identify it. The sepals form ribs around the hypanthium, giving it a turbine-like appearance. Seeds of S. turbinatum are pale orange and around 0.2 mm long.
Stylidium graminifolium, the grass triggerplant, is a dicotyledonous plant that belongs to the genus Stylidium. This species used to belong to the Stylidium graminifolium complex, but the name was conserved for this single species when two others were split from the complex and introduced as new species in 2001. S. graminifolium is endemic to Australia and is one of the Stylidium species with the widest distribution throughout Australia. It is a perennial plant with grass-like leaves and is easily cultivated. It has been considered to be a carnivorous or protocarnivorous plant because it possesses glandular trichomes underneath the flowers that can trap and digest prey.
Repentes is a section in the subgenus Tolypangium. Repentes is a group of creeping triggerplants known as the locket triggerplants, related to subgenus Nitrangium section Appressae. They possess adpressed stem leaves bearing a small basal spur and uni-flowered inflorescences. Because section Repentes morphologically resembles the other creeping triggerplants in section Appressae, Allen Lowrie et al. (1999) proposed all species in this section be moved to section Appressae and Repentes be placed into synonymy. Juliet Wege (2006), however, argued that these species are morphologically distinct from those in section Appressae, citing trichome and column cunabulum structure as distinctions that separate the sections.
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.
Stylidium tenerum, the swamp triggerplant, is a dicotyledonous plant that belongs to the genus Stylidium that was described by Curt Polycarp Joachim Sprengel in 1826. Robert Brown had described this species in 1810 under the name S. tenellum, a name which had already been used for another species in 1805 by Olof Swartz. To add to the confusion, Rica Erickson had described and illustrated this taxon in 1958 under the name S. uliginosum, another currently accepted name for a related species.
Stylidium ericksoniae is a dicotyledonous plant that belongs to the genus Stylidium. It is an annual plant that grows from 6 to 15 cm tall. The linear or deltate leaves, about 20-100 per plant, are mostly in terminal rosettes but with some scattered along the elongate stem. The leaves are generally 4.0-9.5 mm long and 0.6-1.1 mm wide. Petioles are absent. This species produces 1-20 scapes per plant. Inflorescences are 5–11 cm long and produces a single pink or mauve flower that blooms from March to August in the southern hemisphere. S. ericksoniae is endemic to the northern areas of the Northern Territory of Australia. Its habitat is recorded as being damp sand near sandstone rocks or on swampy drainage channels. It's been found in association with Micraira and Pandanus species. S. ericksoniae is most closely associated with S. pedunculatum. Its conservation status has been assessed as data deficient.
Levenhookia, also known as the styleworts, is a genus of ten recognized species in the family Stylidiaceae and is endemic to Australia. The genus is restricted to Western Australia almost exclusively with a few exceptions: L. pusilla's range extends into South Australia, L. dubia's range extends through South Australia into Victoria and New South Wales, L. sonderi is native only to Victoria, and L. chippendalei is also found in the Northern Territory.
Stylidium aceratum is a dicotyledonous plant that belongs to the genus Stylidium. It occurs within the south west region of Western Australia
Stylidium calcaratum, the book triggerplant, is a dicotyledonous plant that belongs to the genus Stylidium. It is an ephemeral annual that grows from 5 to 10 cm tall but can grow larger at 20–30 cm tall in damp forest or scrub habitat. The few ovate leaves produced by this plant form basal rosettes around the stem. The leaves are around 3–5 mm long on short petioles. The scapes are 2–30 cm tall and produce single flowers in smaller plants and up to nine flowers in larger, more robust plants. Flowers are pink or white with red spots or lines at the individual petal bases. The petals are vertically paired and will fold over to meet each other at night or in adverse weather conditions. S. calcaratum is endemic to Australia and has a distribution that ranges from Victoria through South Australia and into Western Australia. Its habitat is recorded as being wet flats or near creeks and seepages. Pollination is achieved by a grey fly, Comptosia cuneata.
Stylidium ceratophorum is a dicotyledonous plant that belongs to the genus Stylidium. It is an annual plant that is endemic to the Kimberley region of Western Australia and northern parts of the Northern Territory. It attains a height of 12–30 cm with a basal rosette of small leaves. The leaves are petiolate, obovate, or lanceolate and are only 0.2–1 cm long. Solitary scapes are produced that bear golden yellow or orange flowers, 7–9 mm across. Its habitat has been reported as being sandy soils on creek margins in the presence of Stylidium rubriscapum and Stylidium diceratum or in river paperbark stands. S. ceratophorum appears similar to S. diceratum and may be confused with the species since they both have orange flowers. S. ceratophorum's corolla is twice as large as S. diceratum, though, as well as the deeply divided posterior corolla lobes of S. ceratophorum.
Stylidium diceratum is a dicotyledonous plant that belongs to the genus Stylidium. The specific epithet diceratum is Greek for "two horns", referring to the two appendages that are present on the bend of the gynostemium. It is an annual plant that grows from 15 to 35 cm tall. The longer leaves are lanceolate and the shorter ones are spathulate, forming a basal rosettes around the stem. The leaves are around 5–8 mm long and 0.2-2.5 mm wide. Inflorescences are around 6–15 cm long and produce flowers that are orange with dark orange and pink veins and bloom from June to August in their native range. S. diceratum is only known from the type location, which is at creek crossings on the road to Beverley Springs in the Kimberley region of Western Australia. Its habitat is recorded as being sandy soils on creek margins. It grows in the presence of S. ceratophorum, S. rubriscapum, Drosera caduca, D. paradoxa, Byblis liniflora, and Grevillea pteridifolia. S. diceratum is most closely related to S. longicornu, but it can be confused with S. ceratophorum, which also has an orange corolla but twice as large.
Stylidium edentatum is a dicotyledonous plant that belongs to the genus Stylidium. It is an annual plant that grows around 6 cm tall. The elliptical leaves form a basal rosettes around the stem. The leaves are around 0.3-0.8 mm long with recurved margins. Inflorescences are produced on solitary scapes and bear flowers that are white with rose-coloured markings at the base of the corolla lobes and two tooth-shaped throat appendages present. S. edentatum was a previously overlooked species that is related to and appears similar to S. calcaratum and S. ecorne. Allen Lowrie and Sherwin Carlquist described this species in 1989 and argued that if S. ecorne is considered distinct from S. calcaratum, then certainly S. edentatum warrants placement at the species level. It differs from S. calcaratum and S. ecorne by the long petioles on its recurved leaves, and the cuneate, obtuse, and unlobed posterior corolla lobes. They also have a distinctive lateral toothlike appendage at the base of each posterior corolla lobe. S. edentatum is endemic to southwestern Western Australia.
Stylidium weeliwolli is a dicotyledonous plant that belongs to the genus Stylidium. It occurs in the North West of Western Australia
Stylidium inaequipetalum, the Ayers Rock triggerplant, is a small herbaceous perennial plant in the genus Stylidium. It grows from 7 to 40 cm tall. Oblanceolate leaves, about 20-100 per plant, form a basal rosette with stems absent. The leaves are generally 15–81 mm long and 2–8 mm wide. This species produces 1-11 scapes per plant. Inflorescences 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 and Western Australia. 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, though it is also closely allied with S. debile.
Stylidium imbricatum, the tile-leaved triggerplant, is a dicotyledonous plant that belongs to the genus Stylidium. It is an herbaceous perennial that grows from 12–50 cm tall and has divided stems covered with tile-like leaves that are arranged in a spiral formation around the stem. The ovate-elliptic leaves are basifixed and held closely against the stems. The leaves are around 1.5-1.8 mm long and 0.6-0.8 mm wide. Terminal inflorescences are racemose or spike-like and produce flowers that are reddish violet with laterally-paired lobes and bloom from April to May in their native range. S. imbricatum is only known from south-western Western Australia in Stirling Range National Park and Porongurup National Park south-east to Cheynes Beach. Its habitat is recorded as being sandy or laterite soils in swampy areas, rocky slopes, or heathland. S. imbricatum is distinct within its subgenus because it possesses obovate sepals. Its conservation status has been assessed as secure.
Stylidium leeuwinense is a species that belongs to the genus Stylidium. The specific epithet leeuwinense refers to the Cape Leeuwin region in Western Australia where the type location for this species is. It is an herbaceous perennial that grows from 15–60 cm tall and has divided stems covered with tile-like leaves that are arranged in a spiral formation around the stem. The lanceolate leaves are basifixed and held closely against the stems. The leaves are around 2.5-3.5 mm long and 0.5-0.8 mm wide. Terminal inflorescences are racemose or spike-like and produce flowers that are reddish purple with laterally-paired lobes and bloom from February to May in their native range. S. leeuwinense is only known from south-western Western Australia along the coast from Augusta to Denmark. Its habitat is recorded as being black, peat-sand soils in swampy areas or heathland. S. leeuwinense, along with S. preissii, is distinct within its subgenus because it possesses leaves without an apical mucro. It differs from S. preissii by its spike-like racemes.
Stylidium preissii, the lizard triggerplant, is a species that belongs to the genus Stylidium. It is an herbaceous perennial that grows from 5–18 cm tall and has divided stems covered with tile-like leaves that are arranged in a spiral formation around the stem. The broadly trullate leaves are basifixed and held closely against the stems. The leaves are around 1.9 mm long and 1.0 mm wide. Inflorescences are umbellate racemes and produce flowers that are white, pale pink, or dark pink and bloom from November to December in their native range. S. preissii is only known from south-western Western Australia from Bremer Bay to Israelite Bay with a few populations near Jandakot. Its habitat is recorded as being white sandy soils in open heathland. S. preissii is distinct within its subgenus because it possesses a strap-like gynostemium column with a dilated cunabulum.
