quillwort
/ˈkwɪlˌwɔrt/
noun
- A small, aquatic or semi-aquatic plant with long, narrow, quill-like leaves, belonging to the genus Isoetes.
- The quillwort grows at the bottom of shallow ponds and lakes.
- We spotted a rare quillwort while hiking near the marsh.
- Quillwort leaves look like stiff green quills rising from the mud.