1. School of Sciences, Lautoka Campus BIO509 Botany Lecture 12: Ferns and Allies Seedless Vascular Plants

3. Four phyla of seedless vascular plants
Phylum Psilophyta (whisk ferns).
Phylum Lycophyta (club mosses and quillworts).
Phylum Equisetophyta (horsetails and scouring rushes).
Phylum Polypodiophyta (ferns)

4. Learning outcomes
Know the distinguishing features of seedless vascular plants.
Know the similarities and differences amongst bryophytes, seedless vascular plants and higher plants.
Know the differences between the four phyla of seedless vascular plants.
Know the reproductive structures and lifecycle of a fern.
Understand and appreciate the human and ecological significance of seedless vascular plants .

5. These protect the tissues from drying out
Evolutionary trends
As plants move from the aquatic to the terrestrial environment new features developed:
Sterile jackets around the gametangia.
Embryos within protective tissues.
Cuticle.
Internal vascular tissue system (xylem and phloem).
These protect the tissues from drying out

6. These lower plants do not have seeds
True leaves
Roots – for absorption and anchorage
Smaller gametophytes
Larger sporophytes
Apical meristem (subapical in bryophytes) allows branching
More light interception/ reproductive structures
Lignin (support)
Tissue systems (dermal, vascular, ground)
These lower plants do not have seeds

7. Lets learn some terminologies first

8. Vascular Tissue System
Xylem- plant tissue that conducts water and minerals. Has Tracheary elements
Tracheids
Vessel elements
Phloem- plant tissue that conducts food (mainly sucrose). Has Sieve elements

9. Vascular Plant Terminology 1
Leaves- photosynthetic, principal lateral appendages of the stem.
Microphylls - small leaves that contain a single strand of vascular tissue.
Megaphylls - large leaves that contain multiple strands of vascular tissue.

10. Vascular Plant Terminology 2
Homosporous- production of one type of spore from one kind of sporangium.
Heterosporous- production of two types of spores from two different kinds of sporangia.

11. Vascular Plant Terminology 3
Sporophyll - a modified leaf that bears sporangia.
Sporangium - a structure that produces spores.
Microsporangium - microspores
Megasporangium - megaspores

12. Vascular Plant Terminology 4
Microsporophyll - a modified leaf that bears microsporangia, a sporangium that produces microspores.
Megasporophyll - a modified leaf that bears megasporangia, a sporangium that produces megaspores.

13. Vascular Plant Terminology 5
Strobilus- a reproductive structure consisting of nonphotosynthetic sporophylls; a cone.
Microstrobilus- a microsporangiate cone.
Megastrobilus- a megasporangiate cone.

14. Generalized life cycle of vascular plants

15. Generalized life cycle of vascular plants

16. Phylum Psilophyta – The whisk ferns

17. Phylum Psilophyta – The whisk ferns
Resemble green whisk brooms.
Habitat- epiphytic or on rich soils
Sporophyte has dichotomously
forking stems
No true leaves or roots
Rhizoids function as roots
Grow up to 30 cm
Unique features:
Stems and sporophytes have neither true leaves or roots
Stems and rhizomes that fork evenly.

19. Enations – green superficial leaf like, vein less photosynthetic tissues are spirally arranged along the stems.
Photosynthesis takes place on the stem
Centrally cylinderal xylem is surrounded by phloem

20. Psilotophyta are native to tropical and sub tropical regions.
Native to Australia and the South Pacific

21. Reproduction Sporangia are at tips of branches.
Gametophytes are bisexual, resemble portions of the rhizome and have a mycorrhizal fungus.
Homosporous and spores produced
in sporangia (fused into
synangia in Psilotum)
Gametophyte
Sporangia

22. Psilotum reproduction
Homosporous life cycle

23. Human and ecological relevance of whisk ferns.
Little economic importance.
Spores have oily feel and were used by Hawaiian men to reduce loincloth skin irritations.
Hawaiians also boiled it to make a laxative liquid.

24. It is said that the species Psilotum nudum is one of the very old plants.
Psilotum resembles the first land plants that appeared on the globe about 400 million years ago.
First land plants had naked stems and terminal sporangia.

25. Extinct Seedless Vascular Plants
Representatives ( MYA)
Rhyniophyta
Zosterophyllophyta
Trimerophytophyta

26. Cooksonia, a vascular plant of the Silurian period
Cooksonia, a vascular plant of the Silurian period. Note tall stature and large branched sporophyte with numerous sporangia. Psilotum is similar to Cooksonia.
Rhizome (underground horizontal stem)

27. Questions??