Outline
• Introduction• Phylum Hepaticophyta - Liverworts• Leafy Liverworts• Phylum Anthocerophyta - Hornworts• Phylum Bryophyta - Mosses
Introduction
• About 23,000 species of bryophytes. Include mosses, liverworts, and hornworts. Habitats range in elevation from sea level
up to 5,500 m or more. Bryophytes of all phyla often have
mycorrhizal fungi associated with their rhizoids.
In some instances, fungi apparently are at least partially parasitic.
Introduction
• Peat mosses are ecologically important in bogs.
• Luminous mosses are found in caves and in other dark, damp places.
• None have true xylem or phloem. Many have hydroids.
• Exhibit alteration of generations.
Phylum Hepaticophyta
• Liverworts Structure and Form
- Most common liverworts have flattened, lobed thalli.
Gametophyte stage develops from spores.
When spores germinate they may produce immature gametophyte (protonema).
Phylum Hepaticophyta
• Thalloid Liverworts Best known species are in the genus Marchantia.
- Thick thallus that forks dichotomously as it grows.
Consists of parenchyma cells with few, if any, chloroplasts.
Leafy Liverworts
• Always have two rows of partially overlapping “leaves” whose cells contain distinctive oil bodies. Often have folds and lobes.
• Archegonia and antheridia are produced in cup-like structure. At maturity, sporophyte capsule may be
pushed out as the seta elongates.- Germinating spore produces a
protonema.
Phylum Anthocerophyta
• Hornworts Structure and Form
- Mature sporophytes look like miniature greenish-blackish rods.
Only about 100 species worldwide. Thalli have pores and cavities filled
with mucilage, that often contain nitrogen-fixing bacteria.
Hornworts
• Asexual Reproduction Fragmentation Separation of lobes from thallus.
• Sexual Reproduction Archegonia and antheridia are produced in
rows beneath the upper surface of the gametophytes.
- Have both unisexual and bisexual plants.
Phylum Bryophyta
• Mosses Structure, Form, and Classes
- About 15,000 species of mosses currently known.
Divided into three classes: Peat Mosses True Mosses Rock Mosses
Mosses
• “Leaves” of moss gametophytes have no mesophyll tissue, stomata, or veins. Blades are nearly always one-cell thick,
and are never lobed or divided. Initially formed in three ranks and usually
end up appearing to be arranged in a spiral or alternately on an axis that twists as it grows.
• Sexual Reproduction:
Phylum Bryophyta
• Human and Ecological Relevance Pioneer Species of Primary Succession Indicators of Surface Water Packing Material Peat Mosses
- Soil Conditioner- Poultice Material- Fuel