Baron Sir Ferdinand Jacob Heinrich von Mueller, KCMG (German: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist.

He was appointed government botanist for the then colony of Victoria, Australia by Governor Charles La Trobe in 1853, and later director of the Royal Botanic Gardens in Melbourne.

Apprenticed to a chemist at the age of 15, he passed his pharmaceutical examinations and studied botany under Professor Ernst Ferdinand Nolte (1791–1875) at Kiel University.

[2] Mueller thought to open a chemist's shop in the gold diggings, so in 1851, he moved to Melbourne, capital of the new colony of Victoria.

Mueller was appointed government botanist for Victoria by Governor Charles La Trobe in 1853, a post that was newly created for him.

The neighbourhoods of Port Albert and Wilsons Promontory were explored, and the journey of some 1,500 miles (2,400 km) was completed along the coast to Melbourne.

[5] Mueller was then nominated as the botanist to accompany the North Australian Exploring Expedition (1855–1856) led by Augustus Gregory, and decided to join despite initial hesitations.

[6] He explored the Victoria River and other portions of North Australia, was one of the four who reached Termination Lake in 1856, and accompanied Gregory's expedition overland to Moreton Bay.

[4] Mueller, for his part, found nearly 800 species in Australia new to science, such as Macadamia ternifolia (named after his friend and colleague, John Macadam).

In April 1873, Mueller had created the genus Guilfoylia and described William Guilfoyle as "distinguished as a collector [who] evidenced great ardour" and held high hopes for his collecting ability.

He accused Guilfoyle of being a "nurseryman [with] no claims to scientific knowledge whatever" and of getting the job due to being related to the wife of the responsible minister.

[12] In 1857, Mueller applied for and was granted the degree of Doctor of Medicine of the University of Rostock;[13] in 1883, he was awarded the Clarke Medal by the Royal Society of New South Wales.

In 1871, King Karl of Württemberg gave him the hereditary title of Freiherr, to mark his distinction in 'natural sciences generally and in particular for the natural history collections and institutions of Our Kingdom'[17] He was then known as Baron Sir Ferdinand von Mueller.

Two hundred and twenty-five women and girls, the youngest of which was six years of age, collected plant specimens and mailed them to Mueller for cataloging.

[23]: 99, 105 & 107 He took a leading part in promoting Australian exploration, especially the Burke and Wills expedition, which was the first to cross the continent, and in the various attempts to unravel the mystery which attended the fate of his fellow countryman Ludwig Leichhardt (1813–1848).