These two species of broad-bladed green algae are almost impossible to distinguish in situ. They consist of several broad fronds, translucent green, of about 6 cm width. The surface of these fronds is often marked with holes, tears and folds. U. australis is understood to be much more common in South Australia, and can be abundant in shallow coastal waters, especially in the right conditions, where it can lead to a "green tide".
