noun. any aquatic plant of the genus Ceratophyllum; forms submerged masses in ponds and slow-flowing streams.
noun. liverworts with slender hornlike capsules.
1. Noun, singular or mass While hornwort is a tropical pond plant, it is able to survive winter climates. 2. Adjective The thalli of most hornwort species tend to be several cells thick, except for those in genus Dendroceros.
