Plants of Dendrobium bigibbum were first collected by a Dr Thomson on Mount Adolphus, a small island about 18 km north-east of Cape York. It does not occur near Cooktown. Dendrobium phalaenopsis was described by Robert FitzGerald, Surveyor General of New South Wales in 1880. The specific name phalaenopsis from the Greek ' phalaina ', meaning 'moth', due to the flower's resemblance to a moth. Dendrobium is a very large genus of more than 1400 species in south and east Asia and in the south-west Pacific.
Dendrobium belongs to the orchid family, the largest family of flowering plants.
This family is distributed widely throughout the world, with the greatest number in tropical areas. The common name, Cooktown Orchid, refers to the northern Queensland town, Cooktown, which lies within the distribution of the species on the Endeavour River, named by Captain Cook after his ship was repaired there in 1770. Plants are up to 80 cm in height, comprising 3-20 flowering canes up to 1.5 cm in diameter. The stems bearing the flowers are 10 to 40 cm long, carrying up to 20 flowers. Each flower is about 3 to 6 cm wide and usually coloured deep to pale lilac, or rarely white.