Columbia subject headings:
Harvard subject headings:
Botanists--British Isles--Biography--Congresses.
Botanists--Great Britain--Biography--Congresses.
Botany--British Isles--Research--History--Congresses.
Plant collectors--British Isles--Biography--Congresses.
Plant collectors--Great Britain--Biography--Congresses.
Princeton subject headings:
Botanists--Great Britain--Biography--Congresses.
Botany--Great Britain--History--Congresses.
Plant collectors--Great Britain--Biography--Congresses.