Ceratophyllum -  Ceratophyllum is a cosmopolitan genus of flowering plants commonly found in ponds marshes and quiet streams in tropical and in temperate regions. They are usually called hornworts although this name is also used for unrelated plants of the division Anthocerotophyta.Ceratophyllum grows completely submerged usually though not always floating on the surface and does not tolerate drought. The plant stems can reach 1–3 m in length. Given a choice of categories company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, the text refers to which one?
The answer to this question is:
Plant