Glossostigma cleistanthum, also known as mudmat, is a freshwater aquatic plant native to Australia, New Zealand, India and East Africa. It is a cleistogamous plant, which is a type of self-pollinating plant that can propagate using non-opening flowers. Where growth is submerged, the leaves are between 0.5–2.5 inches long and bear closed, self-pollinating flowers. These leaves are nearly sessile and grow along the stem in alternating pairs that resemble rabbit ears. Where water recedes and growth is emergent, the leaves are much smaller, ranging between 0.2–0.5 inches in length. The emergent plants produce insect-pollinated flowers located on short stalks. It belongs to the family Phrymaceae which includes annuals and perennials.