In 1899 Merrill accepted a position with the United States Department of Agriculture in Washington D . C . as an assistant to Frank Lamson-Scribner, an authority on the classification of grasses and a pioneer plant pathologist.
32.
In the aftermath of a flood, in which most of the old vegetation is killed by the high waters and bare patches of new, often very fertile, soil were created, these pioneer plants sprang up like magic, often growing in almost pure stands, but usually disappearing after a single season, as other vegetation pushed them out until the next flood.
