Charles Austin Gardner (6 January 1896 – 24 February 1970) was a Western Australian botanist.
Born in Lancaster, in England, on 6 January 1896, Gardner emigrated to Western Australia with his family in 1909.
Gardner showed an interest in art and botany from youth, and was appointed a botanical collector for the Forests Department in 1920. The following year he was appointed botanist to the Kimberley Exploration Expedition, resulting in his first botanical publication, Botanical Notes, Kimberley Division of Western Australia, in which twenty new species were described. In 1924 he transferred to the Department of Agriculture, and following a departmental re-organisation in 1928 he was appointed Government Botanist and Curator of the State Herbarium. During this time he also wrote about botanical topics in the local Western Australian media including Our Rural Magazine.
He travelled widely and published around 320 papers, the most important of which were in which were Contributions to the Flora of Western Australia in Journal of the Royal Society of Western Australia (from 1923), Enumeratio Plantarum Australiae Occidentalis (1930) and Flora of Western Australia Volume 1, Part 1, Gramineae (1952). He described eight genera and about 200 new species. In 1937 he became the first Australian Botanical Liaison Officer at the Royal Botanic Gardens, Kew.
Gardner was awarded the Medal of the Royal Society of Western Australia in 1949, and the Clarke Medal of the Royal Society of New South Wales in 1961.
He retired in 1962, and died from diabetes at Subiaco, Western Australia, on 24 February 1970, aged 74. His personal botanical collection was bequeathed to the Benedictine Community at New Norcia, but was transferred to the State Herbarium in Perth in June 1970.