Botany 4 Lecture 34 Ferns Fern Allies Gymnosperms

Botany 4 Lecture #34 Ferns, Fern Allies Gymnosperms 1

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Vascular Plants • • First appeared ~ 400 MYA. Continuous xylem and phloem. Underground roots and aerial shoots. Lignin in cell walls for support. 5

Cooksonia Early. Vascular Plant • True Stems, • No Roots • No leaves • Why? ? 6

• Microphyll • Megaphyll 7

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Ferns (and Fern Allies) • Ferns, Equisetum, Psilotum • Ferns are Homosporous. • Many forms from low plants to trees. • Comprised much of Coal Forests. 11

Fern Life Cycle 12

Equisetum “Scouring Rush” 13

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Seeded Vascular Plants • 3 Modifications Aided Seed Plant success: • Gametophytes became reduced and retained in sporophyte. • Pollination evolved, plants no longer tied to water for fertilization. • Evolution of the Seed – embryo in protective package. Seeds replace spores as main means of dispersal. 15

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Gymnosperms • • • Appeared ~ 350 MYA. Naked seeds (no ovary). Four groups: Conifers, Cycads, Gingko, Gnetum. Pollen appears, as do seeds. Flourished with ferns for 200 million years. • As earth became warmer and drier, Gymnosperms radiated and Ferns and Fern Allies became less abundant. 18

Pine Life Cycle 19

What is the Take Home Message? 20

Angiosperms • • • Most widespread and diverse (250, 000 species). One phylum w/ 2 -5 classes. Ovary for protection of embryo. Pollination relationships. Vessels and fibers develop. Flowers and fruits. 21