His father was a curator at the Royal Botanic Garden, Leith Walk, Edinburgh.
[citation needed] He described several of the major conifers discovered in the period, including first descriptions of coast redwood (Taxodium sempervirens D. Don; now Sequoia sempervirens (D. Don) Endl.
and Coulter Pine (Pinus coulteri D. Don), and was the first to treat Sugi (Cupressus japonica Thunb.
[citation needed] Don was librarian to the botanist Aylmer Bourke Lambert and compiled for him, Prodromus florae nepalensis ... London, J. Gale, 1825, based on collections made by the botanists Francis Hamilton and Nathaniel Wallich of the Calcutta Botanic Garden.
[1] In 1938, the London County Council marked Don at 32 Soho Square with a rectangular stone plaque, commemorating him as well as botanists Joseph Banks and Robert Brown and meetings of the Linnean Society.