Website of Tobias Westmeier

Synonyms

• Arachnorchis excelsa (Hopper & A.P.Br. 2001) D.L.Jones & M.A.Clem. 2002
• Calonemorchis excelsa (Hopper & A.P.Br. 2001) Szlach. & Rutk. 2003

Notes

Standing up to 90 cm tall, the aptly named Giant Spider Orchid is among the tallest and largest-flowered Spider Orchids of south-western Australia. Although somewhat similar to other orchids in the White Spider Orchid (Caladenia longicauda) complex, its sheer size, long, drooping sepals and petals, and maroon labellum tip make it easily distinguishable from similar species. The petals and sepals are so long that even the dorsal sepal usually bends over and hangs down from the flower.

The Giant Spider Orchid is restricted to a small area along the Leeuwin–Naturaliste Ridge between Dunsborough and Augusta in south-western WA where it occurs in sandy soils in forests and woodlands, flowering in September and October. Despite their large size, the orchids blend in quite well with the surrounding vegetation and – as a result of their dull colouration – are remarkably difficult to locate, in particular in shady locations.

Photos

References

• Caladenia excelsa in the Australian Plant Name Index
• Caladenia excelsa in the Atlas of Living Australia
• Caladenia excelsa in the Western Australian FloraBase