[1] He was born at Kingston, Jamaica, on 7 February 1776, but his parents removed to Ireland before he was four years of age, his mother being a native of Waterford.
He held the chair of botany until 1844 when he was succeeded by Dr. George James Allman; but he did not long enjoy his well-earned leisure, for he died on 8 December 1846.
His best-known work is a thin quarto entitled 'Analysis per differentias constantes viginti, inchoata, generum plantarum quæ in Britanniis, Gallia, Helvetia .
In 1844 he privately brought out an abstract of a memoir read in 1811 before the Royal Society, but not printed, on the mathematical connection between the external organs of plants and their internal structure.
Allman's son, George (1824–1904),was a mathematician, classical scholar, and historian of ancient Greek mathematics.