Stylidiaceae

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Stylidiaceae (trigger plants) A family of annual or perennial herbs and some shrubs, many of which are xerophytes. The leaves are alternate, or often in a basal rosette, simple, often linear and almost grass-like, and without stipules. The flowers are held on a scape, in racemes or cymes. They are irregular and bisexual or unisexual, with 5 persistent sepals, usually united to form 2 lips. The petals are partially fused, forming a deeply lobed corolla with a small lower lobe and 2 pairs of upright lobes. There are 2 stamens, often fused with the style to form a column which curves partially over the lower lip. When an insect lands on the lower lobe of the flower the column springs up and down, which assists the transfer of pollen to the insect (this mechanism gives the plants their common name). The ovary is inferior, with 2 fused carpels and 1 or 2 multi-ovular locules. The fruit is a capsule containing small seeds. The family is divided into 2 subfamilies and 2 tribes separated by their petal and stamen arrangement. A few species are cultivated as ornamentals. There are 5 genera, with about 170 species, found in tropical and temperate regions of Australia and New Zealand, and in restricted regions of Asia and S. America.