Julius von Röhr

Julius Philipp Benjamin von Rohr (1737–1793) was a Prussian-born botanist and plant collector, naturalist, medical doctor and watercolourist, in Danish service who sent many plants to Europe from South America and the West Indies. He collected male Myristica fragrans flowers on the Isle de Cayenne in about 1784.

He created the genus Melanthera which is closely related to Bidens in 1792, and is commemorated by the monotypic genus Rohria Schreb., native to French Guiana This botanist is denoted by the author abbreviation J.P.Rohr when citing a botanical name.

Von Rohr was an immigrant to Denmark, and in 1757 was appointed as municipal buildings inspector and government land surveyor of the Danish West Indies, now known as the United States Virgin Islands. The Danish crown also commissioned a study of the natural history of the islands. Von Rohr started a botanic garden in Christiansted on the island of St. Croix, corresponding with noted natural history scientists back in Denmark and in Europe. In the 1780s he studied cotton cultivation in the Antilles, exploring as far as Cayenne and Cartagena. By now he had been given the rank of lieutenant colonel.

In the 1790s Denmark considered abolishing the Atlantic slave trade, a measure expected to bring down the flourishing sugarcane plantations of the Danish West Indies. Von Rohr, who by this time had acquired considerable administrative experience of the colony, was asked to investigate the feasibility of establishing plantation agriculture in the vicinity of the old Danish slaving forts of Guinea on the West African coast.

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