English-born plant collector who worked on behalf of Ferdinand Mueller. Oldfield was particularly industrious around the mouth of the Murchison River in Western Australia and in the Huon Valley, Tasmania. He also collected extensively across the Nullarbor Plain towards Adelaide and at Twofold Bay, New South Wales. Born in London, little is known of Oldfield's early life. He was in Australia in the 1840s and walked from Sydney to Melbourne some time late in the decade. In the 1850s he was in Tasmania. He mainly collected plants for Ferdinand von Mueller in Melbourne, but also sent a fair amount of material to George Bentham at Kew in England, for his Flora Australiensis.

With failing eyesight, he returned to his home country in 1863 to seek treatment. It was not successful, however, and he spent his last two decades blind. Joseph Hooker and Mueller both campaigned for the Royal Society to grant him a pension in honour of his services to science (to no avail). Among the many new species collected by Oldfield from the lower Murchison River was Emblingia calceoliflora F.Muell., a peculiar Capparidacean and isolated Western Australian endemic. More than 20 species are named after Oldfield, including Eucalyptus oldfieldii F.Muell. and Acacia oldfieldii F.Muell.

Sources:
J.H. Maiden, 1909, "Records of Western Australian Botanists", Journal of the Western Australian Natural History Society, 2(6): 22
N. Hall, 1978, Botanists of the Eucalypts: 102.