List of sources:
Cape of Good Hope. Annual Reports of the Committees and Curators of Public Parks and Botanic Gardens, 1893; Annual Reports of the Curators and Superintendents of Public Gardens, 1894-1904.
Cape of Good Hope. Report of the trustees of the South African Museum, 1907, 1908.
Cape of Good Hope. Report of the Government Botanist..., 1897, pp. 7-8.
City and Suburban Horticultural Society. [Rules and regulations of the society]. Cape Town: Wynberg Times, 1885.
General directory and guide-book to the Cape of Good Hope and its dependencies..., 1886.
General Directory of South Africa, 1890/1, 1903, 1908, 1909.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to Chalwin, Henry James.
The eponym dictionary of South African plants, at http://www.calflora.net/southafrica/1C-F.html