Ferns, Fern Allies Gymnosperms Botany 4 Lecture #34 Ferns, Fern Allies Gymnosperms

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

Cooksonia EarlyVascular Plant True Stems, No Roots No leaves Why??

Microphyll  Megaphyll 

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

Fern Life Cycle

Equisetum “Scouring Rush”

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.

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.

Pine Life Cycle

What is the Take Home Message?

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.