Its collection of specimens numbers over 320 000, making it the third largest university herbarium in the Southern Hemisphere.

[3][4] Harry Bolus (1834–1911), a rich Cape Town businessman, began his collection in 1865 in Graaff-Reinet, and it is now the oldest functioning herbarium in the country.

[5] After his death, the South African College (which changed its name to the University of Cape Town on April 2, 1918) inherited his herbarium; a library featuring many expensive, unique, and rare books on botany; and a substantial amount of money for the maintenance and expansion of the collection.

The focus is primarily on Cape Province flora, including their taxonomy, invasive plants, biogeography, systematics, and evolution.

The best-known of the several collections of plants in the herbarium are Harry Bolus's set of orchids and heaths,[6] H.M.L.