Stylidiaceae Plant Family

About the Stylidiaceae or Triggerplant Family

Stylidiaceae is a family of dicotyledonous plants that includes around 230 species in 31 genera. These plants are distributed primarily in the southern hemisphere, with the highest diversity found in Australia and New Zealand. Stylidiaceae is known for its unusual floral and vegetative structures, as well as its specialized pollination mechanisms. Many members of this family display remarkable adaptations to fire- habitats, while others are adapted for life in nutrient- soils.

Taxonomy and Classification

Stylidiaceae is classified under the order Asterales, which also includes families such as Asteraceae and Campanulaceae. The family Stylidiaceae is divided into two subfamilies: Stylidioideae and Candolleoideae. The former contains the majority of species and includes 26 genera, while the latter includes only one genus, Candollea.

Within the Stylidioideae subfamily, common genera include Stylidium, Oreostylidium, and Levenhookia. The genus Stylidium is by far the largest and most diverse, containing over 200 species. The plants in this family are characterized by their unique floral morphology, including a modified style that acts as a trigger for pollination. Other diagnostic features include spiral or basal rosette leaves and inflorescences with multiple flowers.

Morphology and Characteristics

Plants within the Stylidiaceae family are quite distinctive in their morphology. They often have basal rosettes of leaves, which may be spirally arranged or alternate along the stem. The inflorescences typically bear multiple flowers, each with five petals and a modified style that acts as a trigger for pollination.

One of the most fascinating features of Stylidiaceae is their trigger- mechanism, which involves the release of pollen when an insect triggers these specialized hairs on the stigma. This allows for more targeted pollination and reduces the risk of self-

Many members of this family are adapted to nutrient- soils and fire- habitats. As such, they often have small or wiry leaves, which help to minimize water loss and protect against heat damage. Some species also produce resin or oil glands, which can help deter herbivores.

Distribution and Habitat

Stylidiaceae is a mostly southern hemisphere family, with the highest diversity of species found in Australia and New Zealand. The family is also represented in parts of Asia, Africa, and South America. Within Australia, Stylidiaceae are particularly abundant in the southwest corner, but can be found across a range of habitats, including forests, heathlands, and scrublands.

Many members of this family are adapted to fire- habitats, where they are able to resprout quickly after a burn. Others are adapted to nutrient- soils, such as those found in bogs or sand dunes. Some species prefer wetter environments, while others are adapted to more arid conditions. As such, the distribution of Stylidiaceae species can vary considerably depending on their specific ecological niche.

Economic and Ecological Importance

While Stylidiaceae is not a particularly economically important family, it plays an important ecological role in many of the habitats where it occurs. Many members of this family are adapted to fire- environments, and play a critical role in post- regeneration. They are often among the first plants to resprout after a burn, and can quickly recolonize areas that have been cleared by fire.

Stylidiaceae is also important from a conservation standpoint; many species within the family are threatened or endangered due to habitat loss and other human activities. Preservation of their unique habitats is essential for maintaining the biodiversity of ecosystems where these plants occur.

Additionally, some members of the family have medicinal properties and are used in traditional medicine practices. For example, tea made from Stylidium hirsutum has been used to treat colds and coughs, while extracts from Oreostylidium subulatum have shown promising anti- and anti- activity in laboratory studies.

Notable Species

Several species within the Stylidiaceae family are particularly noteworthy due to their striking morphology or unique adaptations.

  1. Stylidium graminifolium: This species, commonly known as "triggerplant," is one of the most well- members of the Stylidiaceae family. It has wiry leaves that produce a basal rosette, with inflorescences bearing numerous pink or white flowers. The plant' trigger- mechanism is particularly well- and can be seen in action when an insect lands on the flower' stigma.

  2. Levenhookia dubia: This species is endemic to Western Australia and is known for its small, compact size and bright yellow flowers. It is adapted to sand dune habitats and has specialized roots that allow it to extract nutrients from nutrient- soils.

  3. Phyllachne colensoi: This New Zealand native is notable for its unusual growth habit; it forms a hemiparasitic relationship with tea tree (Leptospermum scoparium) and grows as a stemless rosette on the ground. The plant produces tiny, pale pink flowers that are easily overlooked.

  4. Oreostylidium subulatum: This species is found only in alpine areas of Australia and is known for its distinctive, blade- leaves. It is adapted to high- habitats and is often found growing in bogs or other wetland environments.

  5. Candollea serrata: This monotypic genus is the sole representative of the Candolleoideae subfamily and is found only in southwestern Australia. It is characterized by its small, white flowers and long, narrow leaves.