Watersprite, water horn fern
Native to: Asia, exact native range is unclear
Watersprite (Ceratopteris thalictroides) is considered a pantropical aquatic weed having been widely distributed via the aquarium and fishpond trade. It was reported in South Florida as early as 1878 and can be found in shallow slow moving waters such as ditches, ponds, canals and marshes in South and Central Florida.
Family: Pteridaceae
Habit: Annual aquatic fern
Leaves: Leaf shapes are highly variable and there can be several types and shapes on one plant: some emersed and some floating. The floating leaves are often thick and fleshy, with deep lobes on the margins. One form of emersed leaves may be somewhat wide and relatively flat. Another form of emersed leaves is stiff, finely divided, and frilly. The leaflets may resemble thick needles. These frilly leaves are the reproductive leaves.
Reproduction: Ball-shaped sporangia on the undersides of leaves.
Distribution in Florida: Peninsular Florida
Its range is limited by climate as it cannot survive below 60 degrees Fahrenheit and it also requires high nutrient slow to still waters. However, it is easily spread via spores and plant fragments. Few negative impacts have been reported in the US but it is considered invasive in Western Australia where it has displaced native aquatic vegetation by forming dense floating mats. This case is complex because these Watersprite infestations have also been discovered to provide habitat for rare and endangered invertebrates, so eradication is not considered an option.
Do not purchase. Never release aquarium water into local waterbodies.
Hand pull.
None known.
Research needed.
