William Grant Milne

William Grant Milne (?-1866), was a Scottish botanist.

A gardener at the Edinburgh Botanic Garden, Milne joined the HMS Herald expedition to the southwestern Pacific (1852-1856) as a botanist. The expedition visited, inter alia, Lord Howe Island, New South Wales and Western Australia. Milne was initially accompanied by fellow Scots botanist John MacGillivray, who left the ship in 1855 after a dispute with Captain Henry Mangles Denham.

Milne, the discoverer of several plants, including the rare New Caledonian tree Meryta denhamii which he found growing on the Isle of Pines in 1853 and sent to the Royal Botanical Gardens in Kew, had botanist Berthold Carl Seemann name the plant Meryta denhamii after Captain Denham (for whom the town of Denham, Western Australia was also named). The plant was described from specimens that had flowered in a greenhouse in Kew in 1860.