Orchidaceae (Orchids) >

Caladenia polychroma, known as the Joseph’s Spider Orchids, is endemic to the south-west of Western Australia.

It is a terrestrial, perennial, deciduous, herb with an underground tuber and which often grows in clumps.

Caladenia polychroma (Joseph's Spider Orchid) , Stirling Range National Park WA © Terry Dunham
Caladenia polychroma (Joseph’s Spider Orchid), Stirling Range NP WA © Terry Dunham

It has a single erect, hairy leaf, 70–120 mm long and about 4 mm wide, with one or two relatively large and colourful but smelly flowers. The flowers are borne on a stalk 200–300 mm tall, are creamy in colour, with variably red, pink, yellow and white, approximately 100–150 mm long and 80–120 mm wide.

Caladenia polychroma (Joseph's Spider Orchid) , Stirling Range National Park WA © Terry Dunham
Caladenia polychroma (Joseph’s Spider Orchid), Stirling Range NP WA © Terry Dunham

The sepals and petals have long, thin, drooping, thread-like ends, whilst the dorsal sepal is erect, 45–100 mm long and 2–3 mm wide. The lateral sepals are 45–100 mm long and 3–4 mm wide, curving downwards. The petals are 45–90 mm long, 2–3 mm wide and arranged like the lateral sepals. The labellum is 10–17 mm long, 10–13 mm wide and are cream-coloured to yellow with red lines, spots and blotches. The sides of the labellum have short, blunt teeth and the tip is curled under. There are two rows of anvil-shaped, cream-coloured calli along the mid-line of the labellum.

Caladenia polychroma (Joseph's Spider Orchid) , Stirling Range National Park WA © Terry Dunham
Caladenia polychroma (Joseph’s Spider Orchid), Stirling Range NP WA © Terry Dunham

Flowering period occurs from September to October.

Caladenia polychroma (Joseph's Spider Orchid) , Stirling Range National Park WA © Terry Dunham
Caladenia polychroma (Joseph’s Spider Orchid), Stirling Range NP WA © Terry Dunham
Caladenia polychroma (Joseph's Spider Orchid) , Stirling Range National Park WA © Terry Dunham
Caladenia polychroma (Joseph’s Spider Orchid), Stirling Range NP WA © Terry Dunham
Caladenia polychroma (Joseph's Spider Orchid) , Stirling Range National Park WA © Terry Dunham
Caladenia polychroma (Joseph’s Spider Orchid), Stirling Range NP WA © Terry Dunham

Photographs © Terry Dunham


  • Scientific classification
  • Kingdom: Plantae
  • Phylum: Charophyta
  • Class: Equisetopsida
  • Subclass: Magnoliidae
  • Superorder: Lilianae
  • Order: Asparagales
  • Family: Orchidaceae
  • Genus: Caladenia
  • Species: Caladenia polychroma

Footnote & References

  1. Caladenia polychroma (Joseph’s spider Orchid), Stirling Range National Park WA. Photographs © Terry Dunham
  2. Caladenia polychroma Hopper & A.P.Br., Atlas of Living Australia, https://bie.ala.org.au/species/https://id.biodiversity.org.au/taxon/apni/51399281
  3. Joseph’s Spider Orchid (Caladenia polychroma), iNaturalistAU, https://inaturalist.ala.org.au/taxa/416788-Caladenia-polychroma
  4. Caladenia polychroma Hopper & A.P.Br., Joseph’s Spider Orchid, Western Australian Herbarium (1998–). Florabase—the Western Australian Flora. Department of Biodiversity, Conservation and Attractions, Accessed 1 October 2023), https://florabase.dbca.wa.gov.au/browse/profile/15376
  5. Caladenia polychroma, Wikipedia, https://en.wikipedia.org/wiki/Caladenia_polychroma
  6. Caladenia polychroma, Joseph’s Spider Orchid, Western Australian Native Orchid Study and Conservation Group Inc, https://wanoscg.com/caladenia/caladenia-polychroma/
  7. The larger Wispy Spider Orchid Group, Orchids of South-West Australia, https://chookman.id.au/wp_orchids/?page_id=2158

OrchidaceaeCaladenia barbarossa (Dragon Orchid) Caladenia bryceana subsp. bryceana (Dwarf Spider Orchid) Caladenia corynephora (Club-lipped Spider Orchid) Caladenia integra (Smooth-lipped Spider Orchid) Caladenia latifolia (Pink Fairies) Caladenia lobata (Butterfly Spider Orchid) Caleana major (Flying Duck Orchid) Caladenia melanema (Ballerina Orchid) Caladenia polychroma (Joseph’s Spider Orchid) Caladenia pulchra (Slender Spider Orchid) Caladenia pusilla (Tiny Caladenia) Caladenia serotina (Christmas Spider Orchid) Caladenia tessellata (Thick-lip Spider Orchid) Cryptostylis ovata (Slipper Orchid) Cephalotus follicularis (Western Australian Pitcher Plant) Dendrobium kingianum (Pink Rock Orchid) Dendrobium speciosum (Rock Orchid) Drakaea glyptodon (King-in-his-carriage Orchid) Elythranthera emarginata (Pink Enamel Orchid) Epiblema grandiflorum (Babe-in-a-cradle Orchid) Drakaea livida (Warty Hammer Orchid) Ericksonella saccharata (Sugar Orchid) Glossodia major (Wax-lip Orchid) Leptoceras menziesii (Rabbit Orchid) Microtis cupularis (Cupped Mignonette Orchid) Paracaleana nigrita (Flying Duck Orchid) Pterostylis cheraphila (Floodplain Rustyhood) Pterostylis ciliata (Hairy Rufous Greenhood) Pterostylis picta (Painted Rufous Greenhood) Rhizanthella johnstonii (Southern Underground Orchid) Spiculaea ciliata (Elbow Orchid) Thelymitra sp. Ongerup (Orange Sun Orchids) Thelymitra speciosa (Eastern Queen of Sheba’s)

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