hornwort

noun3

1. •
   An aquatic flowering plant in the genus Ceratophyllum
2. •
   Any of certain bryophytes, of phylum Anthocerotophyta, with a leafless thallus characterized by a dominant gametophyte stage of the life cycle and a sporophyte stage shaped like a horn.
3. •
   Vernal grasses (Anthoxanthum spp.).