Leptospermum petersonii was first formally described in 1905 by Frederick Manson Bailey in the Queensland Agricultural Journal from a specimen collected by W.J. Peterson on Wilsons Peak in January 1905. Bailey, Frederick Manson (1827 - 1915) was appointed Queensland Colonial Botanist in 1881 and held this post untiL his death. So was 88 when he described this plant. There was a WJ Peterson at Ballarat Mining School in the early 1900s but no information about him otherwise and it may not have been the same person. He is not in Brummitt's list of botanists who have named plants.