Utricularia blackmanii is a bladderwort endemic to Queensland, Australia. The species is named after Archibald Hugh Blackman, who first collected it.
Utricularia blackmanii has a medium-sized purple-coloured flower. The lower corolla lip is skirt-shaped and flares outwards. The palate features numerous shallow, white ridges fringed by dark purple pigment. The upper corolla lip is notched at the centre. The spur is slightly bent with a rounded apex. It is usually thrust backwards at an obtuse angle relative to the lower corolla lip.
The species is best known from Far North Queensland in the tablelands west of Townsville to Cairns. It grows in a range of seasonally wet habitats which dry out during the dry season. I observed it in a grassy forested flat in the valley of granite ranges near Mt Surprise. There, it grew in waterlogged loam alongside Drosera serpens and Utricularia aff. lasiocaulis.
U. blackmanii is somewhat similar to a few purple bladderworts found in Queensland. It is distinguished from the U. dichotoma complex by its white palate ridges (those of U. dichotoma and allied species have yellow palate ridges). It is also fairly similar to U. terraereginae but is not known to overlap in range (U. terraereginae grows on Cape York and has a forwards pointing spur whereas U. blackmanii is found further south and has a backwards pointing spur. It is also similar to U. triflora, which grows in the Northern Territory.