The botanical name refers to Francis James Gillen. He was Telegraph Stationmaster in Alice Springs in 1892 and collaborator with the anthropologist and natural historian Professor Baldwin Spencer, who led the Horn Expedition to Central Australia in 1894. It grows to 5m and produces white flowers in summer and larger but similarly shaped capsules to the related River Red Gum. Common along the ridges of the MacDonnell Ranges and stony hills of Central Australia.