Non-seed tracheophytes Phylum:Pteridophyta-True Ferns

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).

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 ( cells with thick walls) and stomium cells (with weak walls) Spores dispersed under dry condition by breaking of stomium cells

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.

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.

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

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

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