BSC 2011 Lecture Notes - Lecture 8: Motility, Gymnosperm, Plant Reproductive Morphology
15 Sep 2016
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Gymnosperms- seed plants that do not form flowers and fruits: ovules and seeds are not protected by ovary or fruit tissue. Some species have berries which are modified cones: have only tracheids as the water-conducting and support cells within the xylem. Helps prevent air bubbles in the winter prevents freeze: 4 groups. Ancient group of seed plants: 300 species, palm-like appearance, few branches, soft wood, dioecious- separate male and female plants, sperm with flagella, nostoc in roots (nitrogen fixation) Leaves usually reach 2-4m in length: welwitschia- has only 2 huge leaves that grow continuously from the base. Ephedra: toxic, used in diet pills, sudafed. Megastrobilus- female cone, seeds protected by woody scales (familiar woody cone) Microstrobilus- male pollen-bearing cone (usually herbaceous, not woody) Common, dominate forests at high latitudes and high. Usually have male and female parts on the same plant: monoecious. Well-branched trees with simple leaves: usually needle-like or scale-like, reduced megaphylls.
