On April 2nd of this year Dr P. Jansen, agrostologist and honorary member of the staff of the Rijksherbarium, suddenly passed away at Amsterdam, 73 years old. Pieter Jansen was born at Rotterdam on January 25th, 1882. Trained to be a teacher, his appointment as such followed in 1900. His study in mathematics soon led to his appointment to a secondary school at Rotterdam and afterwards, in 1912, to the Municipal Training School for Teachers at Amsterdam, of which he filled the post of director from 1936 until his retirement a few years ago.