What Is a Hornwort? Tiny Land Plants and the Pond Plant of the Same Name
A hornwort is a small land plant named for its tall horn shaped spore stalks. The name also gets used for a rootless pond plant better known as coontail.
The short answer
A hornwort is a small flat green land plant. UC Museum of Paleontology says the name refers to its tall narrow horn shaped sporophytes. Pond hornwort is a different plant. Rutgers Extension says coontail is sometimes called hornwort. It is a submerged plant with no true roots.
What does a land hornwort look like?
UCMP says most hornworts are small greasy blue green patches. They grow by streams plus in disturbed fields. The horn is the sporophyte. It stays fixed to the flat body plus grows from basal cells all its life. UCMP says that trait is unique to hornworts. To release spores, the horn splits lengthwise in two. Most hornworts have one large chloroplast per cell.
| Option | What it does | Source |
|---|---|---|
| Blue green patch | Plant body | Introduction to the Anthocerotophyta |
| Horn | Spore stalk | Introduction to the Anthocerotophyta |
| Split tip | Releases spores | Introduction to the Anthocerotophyta |
What lives inside a hornwort?
UConn Bryology says colonies of cyanobacteria called Nostoc live inside the hornwort thallus. UCMP adds that pseudoelaters sit among the spores inside the horn.
Nostoc: lives in thallus. Pseudoelaters: among spores. One chloroplast: per cell.
What is pond hornwort?
Rutgers says coontail is a dark green submerged perennial that lacks true roots. Its stiff leaves grow in whorls of five or more with forks plus teeth. It can pass 15 feet plus stays green through winter. Mississippi State says stems can reach 10 feet or more plus break easily. It notes up to 12 leaves per whorl, each under 0.6 inch. Rutgers says coontail gives cover for young fish plus takes up nutrients from the water.
No true roots: rootless plant. Leaf whorls: five to 12. Brittle stems: break easily.
Troubleshooting
Green patch with horns? That is a land hornwort per UCMP.
Bushy plant in a pond? Rutgers says that is likely coontail.
Stem pieces everywhere? Mississippi State says coontail stems are brittle.
Kind Seed Co shares these plant notes for growers of all kinds. For more on plant parts see cannabis leaf anatomy and pond water for cannabis. Read companion plants when growing marijuana for garden pairings. See growing cannabis near trees for site notes.
Sources
- Introduction to the Anthocerotophyta, UC Museum of Paleontology, Berkeley
- Classification of the phylum Anthocerotophyta, University of Connecticut Bryology
- Coontail (Ceratophyllum demersum), a native aquatic plant (FS1236), Rutgers Cooperative Extension
- Coontail, Ceratophyllum demersum, Mississippi State University Extension
FAQ
Are hornworts mosses?
No. UConn Bryology classifies hornworts in their own phylum, the Anthocerotophyta.
Is pond hornwort the same as coontail?
Yes. Rutgers says coontail is sometimes called hornwort.
Does pond hornwort have roots?
No. Rutgers plus Mississippi State say coontail lacks true roots.
Where do land hornworts grow?
UCMP says they grow along streamsides plus in disturbed fields.
How long can coontail grow?
Rutgers says it can grow past 15 feet. Mississippi State says stems reach 10 feet or more.
