Johannes Ludwig Emil Robert von Hanstein (15 May 1822 – 27 August 1880) was a German botanist who was a native of Potsdam.
He attended classes at the Gärtnerlehranstalt (Institute of Horticulture) in Potsdam, and later studied sciences in Berlin, obtaining his doctorate in 1848.
In 1855 he was a lecturer of botany at the University of Berlin, and six years later became curator of the royal herbarium.
[1] With his close friend, Nathanael Pringsheim (1823–1894), he conducted pioneer research on the fertilization process in ferns.
[2] He was also an editor of the journal Botanische Abhandlungen aus dem Gebiete der Morphologie und Physiologie (Botanical treatises from the areas of morphology and physiology).