1. Kingdom Plantae Phylum Tracheophyta Class Psilophytes and Ferns
by Jaime Crosby CHS

2. Tracheophytes are “true” land plants because they have evolved ways of freeing themselves from dependence upon wet environments

3. Adaptations for land Vascular tissue
Xylem contains tracheid cell (thus “tracheophytes”!) which carry water from the roots to all parts of the plant.
Thick, strong cell walls of tracheid cells strengthen stems of plant and support primary growth
Phloem for downward sugar transfer from site of photosynthesis in leaves

4. True Roots and True Leaves
Roots contain a vascular cylinder which is a central area of the root that houses xylem and phloem
Veins house xylem and phloem in leaves
Cuticle retains water in leaves

5. Take a step back to: The first vascular plants
Psilophytes
Discovered in fossils and dated back to 400 Million years
Small, creeping plants that had primitive xylem and phloem
No true roots or leaves
Some scientists believe they are extinct, others believe there are still two living Psilophytes

6. Are they Psilophytes or do they belong in another classification?
Lycopodium common name: Club Moss
Looks like a mini-pine tree (9 cm tall)
Small, scale-like leaves that cling to the stem
Horsetails (Sphenophytes) common name: Equisetum
Grow 1 meter tall
Have true roots, stems and leaves (vasc.)
Contain abrasive silica crystals
Used in colonial times to scour pans

7. Club Moss Horsetail

8. Tracheophytes: Ferns Evolved about 400 MYA 11,000 species exist
Have vascular tissue, strong roots and creeping underground stems called Rhizomes

9. Most abundant in wet or seasonally wet areas like the Pacific Northwest
Can grow as large as small trees
Have large leaves called Fronds

10. Alternation of Generations in Ferns
Actual Fern is Sporophyte (2N) generation
Ferns still depend on water for the sperm to swim to the egg
Haploid spores are produced in sporangia which are grouped into SORI on the underside of the frond

11. When ripe, spores get released from the sporangia and carried away by wind or water
If conditions are right, spores will germinate into haploid gametophytes
Grow root-like rhizoids
Flattens out into Prothallus, the heart-shaped gametophyte

12. Prothallus Archaegonia and Antheridia are located on underside
Mature antheridium release sperm
Fertilization occurs when ground and prothallus are covered with water so sperm can swim to egg in archaegonia

13. Diploid zygote immediately begins to grow into a new sporophyte plant (fiddlehead) with rhizomes and a frond.
Fronds die in winter, but rhizomes live through the winter to sprout again.

14. Summary of Fern Life Cycle
Alternation of Generations is present: Sporophyte is dominant, gametophyte is dependent.
Sporophyte is well developed with true vascular tissues
Gametophyte is tiny, lacks vascular tissues and can only live for a short time in moist areas
Sexual reproduction still requires water

16. A final thought…
Why are ferns better adapted to life on land than mosses?