The water sprite Ceratopteris cornuta has been placed in the species C. thalictroides by various authors. In aquaristics, however, those forms with more coarsely pinnate/lobed leaves are known under the name of C. cornuta, and those with more finely pinnate leaves as C. thalictroides.
Ceratopteris richardii is quite similar to C. cornuta and can only safely be discerned by close examination of the spores. This species is used as model organism in plant genetics. It is even possible that C. richardii is kept in the hobby, however, that it is mistaken for C. cornuta.
Like Ceratopteris thalictroides, C. cornuta can be planted in the substrate as well as cultivated as a floating plant.
To be continued ...
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