Robert Brown FRSE FRS FLS MWS (21 December 1773 – 10 June 1858) was a Scottish botanist and paleobotanist who made important contributions to botany largely through his pioneering use of the microscope.

As a child Brown attended the local Grammar School (now called Montrose Academy), then Marischal College at Aberdeen, but withdrew in his fourth year when the family moved to Edinburgh in 1790.

[2] Brown enrolled to study medicine at the University of Edinburgh, but developed an interest in botany and ended up spending more of his time on the latter than the former.

He had been nominated to the Linnean Society of London; had contributed to Dickson's Fasciculi; was acknowledged in a number of other works; and had had a species of algae, Conferva brownii (now Aegagropila linnaei) named after him by Lewis Weston Dillwyn.

In 1798 Brown heard that Mungo Park had withdrawn from a proposed expedition into the interior of New Holland (now Australia), leaving a vacancy for a naturalist.

He was not selected, and the expedition did not end up going ahead as originally proposed, though George Caley was sent to New South Wales as a botanical collector for Banks.

Banks approved Flinders' proposal, and in December 1800 wrote to Brown offering him the position of naturalist to the expedition.

[6] Though Brown's brief was to collect scientific specimens of all sorts, he was told to give priority to plants, insects, and birds, and to treat other fields, such as geology, as secondary pursuits.

In addition to Brown, the scientific staff comprised the renowned botanical illustrator Ferdinand Bauer; the gardener Peter Good, whose task was to collect live plants and viable seed for the use of Kew Gardens; the miner John Allen, appointed as mineralogist; the landscape artist William Westall; and the astronomer John Crosley, who would fall ill on the voyage out and leave the ship at the Cape of Good Hope, being belatedly replaced at Sydney by James Inman.

They arrived at the Cape of Good Hope on 16 October, staying a little over two weeks, during which time Brown made extensive botanical expeditions and climbed Table Mountain at least twice.

Many years later he would write to William Henry Harvey, who was considering emigrating there, that "some of the pleasantest botanizing he ever had was on Devil's Mountain, near Cape Town, and he thought I could not pitch on a more delightful field of study.

For three and a half years Brown did intensive botanic research in Australia, collecting about 3400 species, of which about 2000 were previously unknown.

The list of major Australian genera that he named includes: Livistona, Triodia, Eriachne, Caladenia, Isolepis, Prasophyllum, Pterostylis, Patersonia, Conostylis, Thysanotus, Pityrodia, Hemigenia, Lechenaultia, Eremophila, Logania, Dryandra, Isopogon, Grevillea, Petrophile, Telopea, Leptomeria, Jacksonia, Leucopogon, Stenopetalum, Ptilotus, Sclerolaena and Rhagodia.

This work was extensively plagiarised by Richard Anthony Salisbury, who had memorised much of the Linnean reading and then inserted it in Joseph Knight's 1809 publication On the cultivation of the plants belonging to the natural order of Proteeae.

[citation needed] In 1818 he published Observations, systematical and geographical, on the herbarium collected by Professor Christian Smith, in the vicinity of the Congo.

Brown's name is commemorated in the Australian herb genus Brunonia as well as numerous Australian species such as Eucalyptus brownii, Banksia brownii and the moss Brown's Tetrodontium Moss (Tetrodontium brownianum), a species which he discovered growing at Roslin near Edinburgh whilst still a student.

[22]: 30 In 1938 the London County Council commemorated Brown, as well as botanists Joseph Banks and David Don, and meetings of the Linnean Society, with a rectangular stone plaque at 32 Soho Square.

[26] In 1827, while examining grains of pollen of the plant Clarkia pulchella suspended in water under a microscope, Brown observed minute particles, now known to be amyloplasts (starch organelles) and spherosomes (lipid organelles), ejected from the pollen grains, executing a continuous jittery motion.

[28] Physicist Phil Pearle and colleagues presented a detailed discussion of Brown's original observations of particles from pollen of Clarkia pulchella undergoing Brownian motion, including the relevant history, botany, microscopy, and physics.