Caladenia plicata, commonly known as the folded caladenia or folded spider orchid, is a species of terrestrial orchid endemic to the south-west of Western Australia. It belongs to the genus Caladenia, a group of orchids known for their often intricate and colorful flowers.
Description
Caladenia plicata is characterized by a single, narrow, hairy leaf, typically 5–15 cm long and 3–8 mm wide, which emerges from an underground tuber. The plant produces a flowering stem up to 30 cm tall, bearing one to three, rarely four, relatively large and showy flowers.
The flowers are usually white, cream, or pale yellow, often adorned with red or maroon streaks and blotches. They measure about 3–5 cm across. The dorsal sepal is erect, while the lateral sepals and petals spread widely, often without the prominent clubbed ends seen in many other spider orchids. A distinguishing feature is the labellum (lip), which is white with prominent red markings, and its margins are typically strongly folded or pleated (hence "plicata"), giving it a textured appearance. The labellum usually has two rows of stalked calli (glandular structures) that extend towards its tip.
Taxonomy and Naming
The species was first formally described by William Henry Nicholls in 1947. The specific epithet "plicata" is derived from the Latin word plicatus, meaning "folded" or "pleated," referring to the distinctive folded margins of the labellum.
Distribution and Habitat
Caladenia plicata is found exclusively in the south-west botanical province of Western Australia. Its distribution extends from the Perth region southwards towards Albany and eastwards to areas like Ravensthorpe. It typically grows in sandy or clayey soils, often in winter-wet flats, and is found in a variety of habitats including woodlands, shrublands, and heath.
Ecology and Flowering
Like many terrestrial orchids, Caladenia plicata is thought to rely on specific fungal associations in the soil for its nutrition. It flowers relatively late in the orchid season for Western Australia, typically from August to October. Its pollination mechanism is likely pseudocopulation, where male insects are attracted to the flower, mistaking it for a female, and transfer pollen in the process.
Conservation Status
In Western Australia, Caladenia plicata is listed as "Priority Four Flora" by the Department of Biodiversity, Conservation and Attractions. This designation indicates that the species is rare, but not considered to be under immediate threat. However, like many native orchids, its populations can be sensitive to habitat loss, land clearing, altered fire regimes, and other environmental disturbances.