Paleobotany

thumb|right|A fossil Betula leopoldae ([[birch) leaf from the Early Eocene of Washington state, approximately 49 million years ago]]

fossilized remains of plants

Pediastrum is a genus of green algae, in the family Hydrodictyaceae. It is a photoautotrophic, nonmotile coenobial green alga that inhabits freshwater environments. The name Pediastrum comes from the Greek root words pedion, meaning "plane", and astron, meaning "star", referring to its overall shape.

geographic corridor between the Mediterranean and the Arabian desert, which connects Africa to Eurasia

classification of organisms based on their morphology

wood that is preserved in the fossil record

Cryptospores are microscopic fossilized spores produced by embryophytes (land plants). They first appear in the fossil record during the middle of the Cambrian period, as the oldest fossil evidence for the colonization of land by plants. A similar (though broader) category is miospores, a term generally used for spores smaller than 200 μm. Both cryptospores and miospores are types of palynomorphs.

chronological outline of major events in the development of plants