Columbia subject headings:
Botanists--Biography.
Botanists--Travel.
Botany--History.
Scientific expeditions--History.
Harvard subject headings:
Biographies
Botanists--Biography
Botanists--Travel.
Botany--History
Scientific expeditions--History.
Princeton subject headings:
Botanists--Biography.
Botanists--Travel.
Botany--History.
Herbaria.
Plant collectors--Biography.
Scientific expeditions--History.