Groups
There are three major groups of bryophytes:
- Mosses (Musci)
- Liverworts (Hepaticae)
- Hornworts (Anthocerotae)
Bryophytes reproduce by means of sexually produced spores. The major groups have similar levels of general morphological complexity, but differ profoundly in their detailed structure and reproductive mechanisms.
Philonotis fontana, a moss
Mosses (Musci):
- Leafy shoots
- Spore capsule develops after its stalk has completed growth
- Spores are released from a mouth at the apex of the spore capsule. Release is often controlled by the united motion of a ring of flexible teeth around the rim of the capsule's aperture that move in response to atmospheric humidity.
Marchantia polymorpha var. polymorpha, a thalloid liverwort
Liverworts (Hepaticae):
- Thallose (wedge-shaped or branching, flattened green cushions) or leafy shoots
- Leaves on ‘leafy shoots’ characteristically occur in two lateral rows of large leaves and one ventral row of smaller leaves
- Spore capsule develops within the female sexual structure on the parent plant prior to the rapid growth of its supporting stalk. When the mature capsule has been elevated on its stalk, the entire capsule wall splits from apex to base into four segments. These bend backwards to expose the mass of spores.
Dendroceros borbonicus, a hornwort
Hornworts (Anthocerotae):
- Thallose (flattened green cushions)
- Horn-shaped spore capsules. Over a short period capsules split from the apex downwards into unravelling narrow strips, releasing mature spores in the process.