He was a leading exponent of lichenology in the early 20th century.
He attended public schools in Lewiston, and later, in Boston where he and his mother moved after his father died.
He entered Harvard University but never finished a degree there.
Around this time he took up an interest in journalism and started writing articles for the newspaper The Beverly Citizen.
Merrill was also a chess player of note, and once won the state championship of Maine.