Glossostigma cleistanthum, also known as mudmat, is a freshwater aquatic plant native to Australia, New Zealand, India and East Africa.

[1] Mudmat prefers to grow in the littoral zone which is the area close to the shore in a lake, sea, or river.

Mudmat is currently causing problems in Rhode Island, New Jersey, and Eastern Pennsylvania, with the earliest record of Mudmat in North America being in 1992 in Hamburg Cove, CT.[4] There is concern for it as an invasive species since it is occurring in areas with species listed as endangered in Connecticut and/or New Jersey.

[3] Some of these species include: Eriocaulon parkeri, Crassula aquatica, Lilaeopsis chinensis, Limosella subulata, Myriophyllum tenellum and Heteranthera multiflora.

[3] Subsequent dispersal is expected to be due to migrating waterfowl, watersheds, boating and fishing activities.