After a hot and dry spring and summer, rains in autumn have spawned the Antelope Greenhood (Diplodium laxum), Scarlet Greenhood (Diplodium coccinum), Summer Greenhood (Diplodium decurvum) and Long-tongue Summer Greenhood (Diplodium aestivum) orchids.

Orange Field Naturalists member and plant ecologist Dr Richard Medd said there are 40 known species of orchids on the mount and the rediscovery reinforces the importance of the reserve.

"The orchids will be nominated as threatened species to be protected in the area," he said.

Many of the locally rare orchids have not been sighted in the area since the 1980s.

Dr Medd said he considers the presence of the orchids to be a good indicator of the health of the grassy forest ecosystems and these areas need nurturing and protection.

In January, another two threatened orchid species native to Mount Canobolas were officially named the Leek Orchid (Paraprasophyllum canobolense) and the Pink Spider Orchid (Caladenia boweri) after local orchid expert Dr Colin Bower discovered the plants and sent the specimens to Australian National Botanic Gardens in 1988.

Orange Field Naturalists member Nigel Hobden was a part of the rediscovery of the Summer Greenhood and Antelope Greenhood orchids.

He said he was "quite stoked" to locate the orchids because it's different from the ones previously found on Mount Canobolas.

"In the late summer of this year, I went for a cross country walk by myself on the mountain and noticed the Antelope Greenhood and knew it was different from the other orchid species," Mr Hobden said.

"After finding the first orchid, it instilled a sense of enthusiasm because if I continued to follow the general walking track I wouldn't have found the rare orchid."

Mr Hobden said his interest in the environment and search for new orchid species peaked since joining the group.