Collecting in Australia
Brown joined the Investigator voyage led by Matthew Flinders in 1801. After the coastal expedition he remained in Australia collecting until 1805. His 1810 Prodromus florae Novae Hollandiae organized botanical findings from this work and contributed extensive material to comparative plant classification.
Nuclei and moving particles
Brown investigated fine structures in plants, describing cell nuclei in 1831 and studying stomata. His microscopic observations of irregular particle movement in water later gave Brownian motion its name. The observation preceded the molecular explanations developed by subsequent physicists.
Collections and scientific societies
Brown managed Joseph Banks’s library and herbarium. When the collections passed to the British Museum, he became the first Keeper of its Botanical Department. His work at the Linnean Society included its presidency from 1849 to 1853, connecting collecting, curatorship and scientific exchange.