Hermann Baum was a German botanist who in 1899 accompanied a scientific expedition led by Pieter van der Kellen to the basins of the Kunene and Zambezi Rivers. The expedition was sponsored by the German Kolonial-Wirtschaftliches Komitee, the Portuguese Companhia de Mossamedes, and the South West Africa Company of London. The research was mainly conducted in south Angola and at some places in northern Namibia. The expedition's comprehensive report, Kunene-Sambesi-Expedition, H. Baum (593p), was edited by Otto Warburg and published by the Kolonial-Wirtschaftliches Komitee in 1903. It dealt mainly with the flora, fauna, and inhabitants of the region and is excellent as far as the natural history of the region is concerned. Upon his return to Germany in 1900 Baum also read a note on the location of Welwitschia mirabilis plants near Mossamedes in Angola, "Die standorte der Tumboa Bainesii, Hook. f. (= Welwitschia mirabilis) bei Mossamedes", which was published in the Notizblatt des Königl. Botanischen Gartens und Museums zu Berlin in 1903. A subsequent paper by him, "Welwitschia mirabilis Hook. f.", appeared in Gartenwelt (1905).
Baum the botanist should not be confused with the German veterinary anatomist Hermann Baum, who published various papers (mainly relating to dogs) from 1886 onwards.