Caladenia patersonii, commonly known as Paterson's spider orchid, is a species of terrestrial orchid in the family Orchidaceae. It is endemic to Tasmania, Australia.
Taxonomy
- Kingdom: Plantae
- Clade: Tracheophytes
- Clade: Angiosperms
- Clade: Monocots
- Order: Asparagales
- Family: Orchidaceae
- Subfamily: Orchidoideae
- Tribe: Diurideae
- Genus: Caladenia
- Species: C. patersonii
The species was first formally described by botanist John Lindley in 1840. The specific epithet patersonii honors William Paterson, a Scottish explorer and colonial administrator in early Australian history.
Description
Caladenia patersonii is a perennial, deciduous herb that grows from an underground tuber. It typically produces a single, erect, hairy leaf measuring 6–15 cm in length and 2–4 mm in width. The inflorescence consists of one to three flowers borne on a slender spike 10–30 cm tall.
The flowers are spider-like, with a dorsal sepal and lateral sepals that are long, narrow, and often slightly drooping. Petals are similarly elongated. The labellum (lip) is white to pale pink, adorned with red or dark maroon calli and marginal teeth, which aid in pollinator attraction. Flowering occurs from September to November in the Southern Hemisphere.
Distribution and Habitat
Caladenia patersonii is restricted to the island of Tasmania. It is found primarily in the central and eastern highlands, occupying open forest, subalpine heath, and grassland habitats. The orchid prefers well-drained, slightly acidic soils and is often associated with low shrubs such as Leptospermum and Acacia species.
Ecology
Like many Caladenia species, C. patersonii engages in a mycorrhizal relationship with soil fungi, which is essential for seed germination and nutrient acquisition. Pollination is typically mediated by native thynnine wasps, which are attracted to the flower’s visual and chemical cues that mimic female wasps.
Conservation Status
The species is listed as "Rare" under the Tasmanian Threatened Species Protection Act 1995. Main threats include habitat loss due to land clearing, inappropriate fire regimes, and competition from invasive plant species. Conservation measures involve habitat protection, fire management, and ex situ propagation programs.
References
- Brown, R. W., & Dixon, K. W. (2000). The Orchids of Tasmania. Hobart: Tasmanian Museum and Art Gallery.
- Jones, D. L. (2006). A Complete Guide to Native Orchids of Australia. Sydney: Reed New Holland.
- Tasmanian Government Department of Primary Industries, Parks, Water and Environment. (2022). Threatened Species Listing Statement for Caladenia patersonii.
Note: All information presented is based on peer‑reviewed botanical literature and official government conservation assessments.