Seedless Plants
Plant
Evolution
Plant Evolution
Nonvascular Seedless plants
– (Ordovician - 475 mya)
 Vascular Seedless plants
– (Devonian - 400 mya)
 Vascular Seed plants
– (Carboniferous - 360 mya)
 Flowering plants
– (Cretaceous - 130 mya)

Plant Evolution
(Common with Algae)
Multicellular and Eukaryotic
 Cell walls made of Cellulose
 Chlorophyll a and b
 Store excess sugar as starch

Charophyceans






Homologous Cell Walls
Peroxisome enzyme
(Photorespiration)
Homologous
Chloroplasts
Sperm ultrastructure
Phragmoplasts (Mitosis
& Cytokinesis)
Genetic Relationships
Adaptations to Terrestrial Life
Apical Meristems
 Multicellular Dependent Embryos
 Alternation of Generation
 Walled Spores produced in Sporangia
 Other Adaptations
– Cuticle, stomata, Xylem & Phloem,
secondary compounds

Apical Meristems
Multicellular Dependent
Embryos
Alternation of Generation
Walled Spores produced in
Sporangia
Other Adaptations
Adaptations in
Shallow Water Algae
Subjected to occasional drying
 Protection of gametes and embryos in
gametangia
 Sporopollenin

Classification of Seedless
Plants

Nonvascular Seedless
plants
– Bryophyta
 Mosses
– Hepatophyta
 Liverworts
– Anthocerophyta
 Hornworts

Vascular Seedless
plants
– Lycophyta
 Club mosses
– Psilophyta
 Whiskferns
– Spenophyta
 Horsetails
– Pterophyta
 Ferns
Nonvascular Seedless Plants
Plant is a thallus (no vascular tissue)
– no true leaves, roots, stems
 Embryophytes
– gametangia
(antheridium and archegonium)
– sporangium (produces spores)

Hepatophyta

Liverworts
– Two forms
leafy (80%)
thalloid (20%)
Hepatophyta

Liverworts
– Reproduction
asexual
(gemmae cups)
sexual
Anthocerophyta

Hornworts
– Similar to
liverworts
except for
sporophytes
– Most closely
related to higher
plants
Bryophyta
Mosses
Bryophyta
Mosses
Vascular Seedless Plants
Formation of vascular tissue
– Xylem (water)
– Phloem (food)
– True leaves, roots, and stems
 Lignin
 Sporophyte generation dominate
 Sperm with flagella

Lycophyta

Lycophytes
– true leaves
microphylls
– true stems
– true roots
– sporophylls
leaves that
produce spores
Psilophyta

Whisk Ferns
– no true leaves
– no true roots
Sphenophyta

Horsetails
– true leaves
microphylls
– true stems
silica
– true roots
Division: Pterophyta
Division: Pterophyta
Fern Life Cycle