Oxalis caerulea, the blue woodsorrel, is a perennial plant and herb in the Oxalidaceae family.
Oxalis grandis, the great yellow woodsorrel, is an annual plant and herb in the Oxalidaceae family.
Oxalis illinoensis the Illinois Woodsorrel, is a species of flowering plant in the woodsorrel family.
Oxalis incarnata is a species of flowering plant in the woodsorrel family known by the common names pale pink-sorrel and crimson woodsorrel.
Oxalis purpurea is a species of flowering plant in the woodsorrel family known by the common name purple woodsorrel.
Reinhard Gustav Paul Knuth (1874–1957) was a German taxonomist, botanist and pteridologist responsible for "Initia florae venezuelensis" in 1928, and numerous contributions to Adolf Engler's "Das Pflanzenreich" on Geraniaceae, Oxalidaceae, Lecythidaceae, and other families.