Bryophytes

Bryophytes are nonvascular, nonwoody plants that include the mosses, liverworts, and hornworts. They have simple internal transport systems (no true roots, stems, or leaves). Although they resemble more complex land plants, they do not contain xylem or phloem. Most species do have structures called rhizoids that attach the gametophytes to the soil and absorb water and minerals. The gametophyte dominates the life cycle. It has leaflike, stemlike, and rootlike parts. Bryophytes usually live in wet habitats. Flagellated sperm require water to reach eggs.

These nonvascular plants show three features that were adaptive during the transition to land:

Mosses

Mosses are the most common bryophytes. Eggs and sperm develop in jacketed vessels (gametangia) at the shoot tips of moss plants. After fertilization, the zygote develops into a mature sporophyte, which consists of a special structure (sporangium) in which the spores develop.

You have probably heard of peat moss and may have used it in gardening or in potting plants. There are actually 350 species of peat moss. Sphagnum is an example. Peat mosses grow in acidic bogs and are important ecosystems of cold and temperate regions. Peat can also be harvested and burned as fuel.

This animation (Audio - Important) describes the moss life cycle.

REVIEW: All are Bryophytes EXCEPT
a. hornworts.
b. liverworts.
c. lycopods.
d. mosses.

REVIEW: Of all land plants, bryophytes alone have independent _____ and attached, dependent _____ .

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