Soon, he changed place with the other Professor of Medicine, Nils Rosén, and thus was responsible for the Botanical Garden (which he would thoroughly reconstruct and expand), botany and natural history, instead.
Pronto cambiou o lugar con outro profesor, Nils Rosén, e así conseguiu a responsabilidade sobre o xardín botánico (que reconstruíu e ampliou minuciosamente), botánica e historia natural.