what are some poisonous plants underwater?
Hygrophila balismica has been reported to be poisonous, but it grows at the surface, as does Water hemlock. In a search of over two dozen texts and references and several hundred web sites, I could find no report of a toxic plant which is entirely under water except algae (called dinoflagellates) and others which cause red tide and similar blooms (called Harmful Algal Blooms). I’m not saying there are none, just that I am having trouble finding them.
