Utricularia benthamii is an affixed aquatic bladderwort endemic to south-west Western Australia. The species is named after George Bentham, a prominent English botanist.
Utricularia benthamii is a medium-sized bladderwort with flowers that reach 2-3cm in diameter. The lower corolla lip is purple, with three well defined lobes in a ‘T-shaped’ configuration. The eastern forms of the plants have a smaller lower corolla lip relative to the western forms. The palate region features a raised clump of several shallow yellow ridges. The upper corolla lip is creamy white in colour. The stolons are thin and radiate into the water column from a central rosette. A trap is borne at the end of each stolon.
The species grows aquatically in shallowly flooded swamps and creek systems, generally in clayey substrates. It blooms in spring as the day length increases and the water level drops and begins to expose the plants to air. It grows along the south coast of WA, extending northwards into the adjacent ranges as well as disjunctly at Cape Le Grand.
The ‘T-shaped’ configuration of the lower corolla lip lobes distinguishes the species from other bladderworts in southern Western Australia. The purple – yellow – cream colouration is shared with some forms of U. paulineae. Utricularia benthamii is distinguished from U. paulineae by its distinctively three-lobed lower corolla lip (that of U. paulineae is semi-circular).