Emphasis is on California, North America, Latin America (especially western and southern Mexico and the Galapagos) and Asia (especially China). Vascular plant families and genera that are particularly well represented include Acanthaceae, Brassicaceae, Carex, Eriogonum, Hydrophyllaceae, Lupinus, Asteraceae (particularly Madinae), Malvaceae, Melastomataceae, Onagraceae, Penstemon, Poaceae, Polemoniaceae and Quercus. The herbarium also contains the largest collection of ornamental plants in California.