Seedless Vascular Plants (Lycophytes & Pteridophytes) and Gymnosperms (Conifers, Cycads, Ginkgo): Key features and reproductive innovations

Notes

# GROUP 2 — Seedless Vascular Plants (Lycophytes & Pteridophytes) A huge upgrade: these plants developed internal pipes for transporting water and nutrients. This lets them grow much taller than bryophytes. ## New features compared to bryophytes: - Vascular tissue — Xylem (water up) + Phloem (food around) - Lignin in cell walls — makes them stiff and strong - True roots, stems, and leaves - Stomata on plant surfaces to control water/gas - Now the Sporophyte is the dominant (big) generation - Still no seeds — sperm still needs water to swim ## Lycophytes: - About 1,000 species today — small, grow on forest floors - In the past (Carboniferous period, 354-290 mya): HUGE trees up to 35 meters tall! - Have a strobilus (cone) — cluster of sporangia on specialized leaves - Example: Lycopodium, Selaginella ## Pteridophytes (Ferns, Horsetails, Whisk Ferns): - Over 12,000 modern species - The plant body you see is the sporophyte - Fern leaves are called fronds - Spore clusters on underside of fronds are called sori - Spores grow into gametophytes; antheridia & archegonia on gametophyte underside **Homospory vs Heterospory:** Most seedless vascular plants make one type of spore (homos...