Henning Eiler Petersen

Henning Eiler (Ejler) Petersen (1877–1946) was a Danish mycologist, botanist and marine biologist. He made a major contribution to unveiling the mysterious die-back of eel grass in Northern European waters in the early 20th Century as a pathogen outbreak.

Petersen's main research was in what was then known as lower fungi - Chytridiomycota and Oomycetes, but he also studied the systematics of Red algae. Parallel to these lines of research, he investigated the intraspecific morphological variation in plant species - which would today be called quantitative genetics.

The Oomycete genus Petersenia is named to his honour.