This member of the Rubiaceae family was given this name by Paul Irwin Forster in 2001. It is found on the Cape York Peninsular, Queensland, Australia, growing as an epiphyte with lots of water and some sun. The caudex can grow to 30 centimetres in diameter, the entire plant to 60 centimetres in height. The flowers are white. The genera name after Greek hydnon meaning 'tuber' and phyton meaning 'plant', after the swollen branches. The species is named after the Latin ferrugineus due to the up to two millimetre long ferruginous trichomes in the inflorescences. Hydnophyttnae KEY. A drawing by Paul Irwin Forster.

