William Henry Harvey (1811-1866), botanist, formed a boyhood passion for natural history which was encouraged at Ballitore School, County Kildare. At 20 he began a long association with William Jackson Hooker who commissioned him to describe certain groups in the new edition of the British Flora and introduced him to many botanists. Through (Sir) Joseph Hooker, Harvey received algal collections from expeditions to the Pacific and southern hemisphere. These he described in his Nereis Australis (London, 1847-49) and as a contributor in J. D. Hooker, Flora Tasmaniae (London, 1860). Harvey wanted to visit New South Wales, but in 1835, through family connections, he became treasurer in Cape Town. There he continued his botanical work, publishing A Manual of the British Marine Algae (1841), and preparing three volumes of Flora Capensis (1859-1865). In 1842 he returned to Dublin, where he became curator of the Trinity College herbarium, professor of botany of the Royal Dublin Society, and in 1856, chair of botany at Trinity College; he held all three posts until 1866. In 1849 he toured the United States as guest of the Smithsonian Institute and Harvard University; later, he published much about American algae. Granted leave by Trinity College he sailed for Western Australia, arriving at Albany on 7 January 1854; after a month at Cape Riche he went overland to Perth where he visited Fremantle and Rottnest and Garden Islands. He collected 10 000 specimens, describing some in 'Some Account of the Marine Botany of the Colony of Western Australia' (Transactions of the Royal Irish Academy of Science, 1855) and naming many algae after botanists in the colony. He reached Victoria in September 1854 and collected in Port Phillip, Westernport Bays and Port Fairy. On advice of Ferdinand von Mueller he discovered at Queenscliff many new algae, naming them after Victorian associates and publishing the collection in Phycologia Australica (1858-1863). In January 1855 he went to Tasmania. At George Town he investigated seaweeds and at Deloraine collected seeds and land plants. He collected seaweeds at Eaglehawk Neck and Dead Island, and also gave much attention to the Port Arthur penal establishment. Returning to Sydney he went by steamer to Newcastle. In the John Wesley he visited New Zealand, Tonga and the Fiji Islands and returned after six months to Sydney. After recuperation at Kiama he sailed by way of Valparaiso for Dublin, arriving in October 1856. Despite failing health Harvey published more monumental works which are still used as working manuals, particularly in Australia. His herbarium is at Trinity College, Dublin, but some duplicates from his travelling sets are in the National Herbarium of Victoria. Two sets of his Algae Australiae Exsiccatae in book form are in the Mitchell Library, Sydney. Also interested in theology, he published Charles and Josiah: or Friendly Conversations Between a Churchman and a Quaker in 1862.