Bryophyta (mosses)
- Bryophytes include the mosses, liverworts,
and hornworts.
- Although they resemble more complex land
plants, they do not contain vascular tissue (xylem or phloem).
- Most species do have rhizoids that
attach the gametophytes to the soil and absorb water and minerals.
- These nonvascular plants show three features
that were adaptive during the transition to land.
- Above-ground parts display a cuticle, for
protection against dessication, with numerous stomata or pores,
for gas exchange.
- A cellular protective jacket surrounds the
sperm-producing and egg-producing parts of the plant to prevent
drying out.
- The embryo sporophyte (small, dependent)
begins life inside the female gametophyte (large, independent).
- Mosses are the most common bryophytes.
- Eggs and sperm develop in the gametangia
at the shoot tips of the familiar moss plants.
- After fertilization, the zygote develops
into a mature sporophyte, which consists of a sporangium
in which the spores develop.
Click on the Internet links below for more
information.
Bryophytes Home Page.
An introduction to the mosses, liverworts, and hornworts from
Southern Illinois University at Carbondale.
Mosses and Allies. The
Natural Perspective's site provides great photos and an introduction
to each of the byophyte groups.
Internet Resources for Bryologists and Lichenologists. Tons of internet links provided by the American Bryological
and Lichenological Society.
Mosses - Reproduction and Life Cycle. An illustrated page by a graduate student at Wake
Forest University. Excellent review of the moss life cycle.
Bryophyta. From Ohio
State University's General Biology course. The page includes notes,
photos, and a diagram of the moss life cycle.