Non-seed tracheophytes

1. Non-seed tracheophytes Phylum:Pteridophyta-True Ferns

2. Phylum: Pteridophytes -True Ferns… • Sporophyte dominant and long-lived • Leaves are large, called fronds • The following steles occur : protostele (all types) and siphonostele (all types) • Spores are borne in sporangia on the underside of leaves (fronds).

3. True Ferns… • In some ferns, sporangia are borne on special branches rather than on ordinary foliage leaves • Sporangia usually clustered into sori (sorus) • Sporangium consist of annulus ( cellswith thickwalls) and stomium cells (with weak walls) • Spores dispersed under dry condition by breaking of stomium cells

4. True Ferns… • Only one kind of spores are produced in most (homosporous) • One kind of gametophyte which bears both antheridia and archegonia. • A few ferns, including a small group called water ferns, are heterosporous.

5. True ferns… • Gametophyte • Formed by germination of spores • small, usually heart-shaped • Antheridia and archegonia on same gametophyte • Ferns still require water for fertilization • Ferns are thought to be the group which gave rise to the seed plants.

6. Phylum: Pteridophyta- Fern allies • 1) Horse tails • Sporophyte consists of a stem with small leaves arranged in groups on a node • Stele is a eustele • Spores in sporangia arranged in terminal cones or strobilus • Plants are homosporous • Gametophytes very small • Only one genus is living- Equisetum

7. Fern allies… • 2) whisk ferns • Most members extinct- fossil record only • Two living genera- Psilotum & Tmesipteris • Sporophyte- dichotomously branched stem with very small scale-like leaves (no v.tis) • Has also underground stem (rhizome) • Stele a protostele (actinostele). only in stem

8. Whisk ferns… • Fertile shoots bear lobed synangium produced by fusion of 3 sporangia • Homosporous • Spores germinate to produce underground saprophytic gametophyte • Archegonia and antheridia develop on same gametophyte