A hornwort is a flowerless, spore-producing bryophyte. It is characterised by its spores which are typically produced in a tapering, horn-like or needle-like capsule that develop from a flattish, green sheet.
All bryophytes have a gametophyte stage and a sporophyte stage and in hornworts the gametophyte consists of a flattish, green sheet called the thallus. The male and female gametes (sperm and eggs) are produced on the thallus and a fertilized egg will develop into a sporophyte. It is the sporophyte that has a tapering horn-like or needle-like structure.
The English word wort means small plant and it is appears in plant names such as liverwort, pennywort and bladderwort. Hornwort, therefore, can be best described as a "small, horned plant".
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