Johannes (Hans) Gottfried Hallier (6 July 1868 – 10 March 1932) was a German botanist born in Jena.
In 1894, Hallier became the second European to climb Mount Kelam (after a certain Dr. Gürtler) and the first to collect specimens of the pitcher plant Nepenthes clipeata.
[3] From 1903 to 1904 he took part in a scientific expedition to India, Ceylon and Maritime Southeast Asia.
He is credited for introducing a phylogenetic classification of flowering plants that became known as the "Hallier system".
[5][6] He published several works on the botany of the Dutch East Indies (now Indonesia), including treatises on the flora of Borneo.