Plant Diversity : Nonvascular
Plants & Seedless Plants
Context
• Archaeplastida
- Red Algae*
- Chlorophytes*
- Charophytes
Green Algae
Land plants
Objectives:
•Become familiar with ancestral features and derived
features relative to their adaptations to the land
environment
•Distinguishing characteristics of nonvascular plants
and seedless vascular plants
•Recognize and identify members of each phylum
•Be familiar with general life cycles of each group
•Identify fossil members and their extant counterparts
in the seedless vascular plants
•Describe homospory and heterospory
Land plants evolved from green algae
Land plants evolved from green algae
Five key traits (ancestral) land plants and charophyceans have in
common:
1. Homologous chloroplast
2. Flagellated sperm cells (structure of sperm)
3. Similarities in cell wall synthesis
4. Peroxisome enzymes
5. Similarities during cell division
Five key traits (derived) appear in nearly all land plants but are
absent in the charophyceans
1. Apical meristems
2. Alternation of generations
3. Walled spores produced in sporangia
4. Multicellular gametangia
5. Multicellular dependent embryos
Land plants evolved from green algae
Non-vascular seedless plants
Bryophytes
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rhizoids
alternation of generations
sporophyte dependent on gametophtye
both generations are multi-cellular
reproduction still relies on water
pores can’t close
Land plants evolved from green algae
Vascular seedless plants
Lycophytes & Pterophytes
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polysporangiate
alternation of generations
sporophyte NOT dependent on gametophtye
both generations are multi-cellular
reproduction still relies on water
pores can’t close
Xylem & phloem
Roots & leaves
Nonvascular - Bryophytes
Lifecycle dominated by the gametophyte
Kingdom Plantae
Phylum Hepatophyta
Phylum Bryophyta
Phylum Anthocerophyta
– Liverworts
– Mosses
– Hornworts
Alternation of
Generations
Rhizoids
Life cycle of Bryophytes
Phylum Hepatophyta - Marchantia
female
male
gemmae cup
Reproductive structures
Gemmae cup
Archegonium
Antheridium
Other structures
Rhizoids
Pores
Thallus
Gametophyte
Sporophyte
Phylum Bryophyta - Polytrichum
Reproductive structures
Archegonium
Antheridium
Other structures
Gametophyte
Rhizoids
Pores
Sporophyte
Thallus
Phylum Anthocerophyta - Phaeoceros
Vascular Seedless Plants
Lifecycle dominated by the sporophyte
Kingdom Plantae
Phylum Lycophyta
Phylum Pterophyta
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– Club Mosses
– Ferns, horsetails,
whisk ferns
Polysporangiate
Sporophyte NOT dependent on gameyophyte
Xylem and phloem
Roots
Leaves
Phylum Lycophyta
– Club Mosses
Lycopodium cernuum
Selaginella sporophyte
Selaginella Lifecycle
Heterospory
Strobilus
Sporangium
Sporophyll
Lignin
Megaspores
Microspores
polysporagiate
Lycopodium
sporophylls
Phylum Pterophyta
Ferns, Horsetails, Whisk ferns
Used to be in 3 phylum but molecular biology strongly supports a
closer relationship between these 3 and grouped them in one
phylum
Ferns – pterophytes
Horsetails – sphenophytes
Whisk ferns – psilophytes
Ferns – pterophytes
Sporophylls
Sporangium
Sori
Next week
Plant Diversity II