Columbia subject headings:
Botanists--Wyoming--Biography.
Botany--Rocky Mountains Region--History.
Nelson, Aven, 1859-1952.
Harvard subject headings:
Botanists--Wyoming--Biography.
Botany--Rocky Mountains Region--History.
Nelson, Aven, 1859-1952.
Princeton subject headings:
Botanists--Wyoming--Biography.
Botany--Rocky Mountains Region--History.
Nelson, Aven, 1859-1952.