(Belgium). Morren was a student of Adolphe Quetelet. Quetelet made plant phenological observations at the Royal Observatory of Belgium in Brussels. He is considered "one of 19th century trendsetters in these matters." In 1839, he started his first observations and created a network over Belgium and Europe that reached a total of about 80 stations in the period 1840-1870.

Morren participated in 1842 and 1843