1. Introduction to the Ferns
A presentation for the LEA
August 16, 2012

2. Introduction to the Ferns
Fern structure
How to identify ferns
Fern life history

3. Fern Structure
leaf (frond)
rhizome (stem)

5. The Leaf (Frond)
blade
leaf (frond)
rachis
pinna
(leaflet)
petiole

6. How to Identify Ferns
Rhizome habit: is the underground stem ± upright or is it long-creeping?
Leaf shape: broadest at base, middle, above middle …?
Leaf dissection: once-pinnate, twice pinnate, etc.
Indument: of hairs, scales, or both?
Sorus shape and position: round and near margin, etc.
Indusium: present or absent
Habitat: swamps, rocky woods, etc.

7. Rhizome habit: is the underground stem ± upright or is it
long-creeping
more or less upright
Rhizome habit: is the underground stem ± upright or is it
long-creeping?

8. Leaf shape: broadest at base, middle, above middle …?

9. Leaf dissection: once-pinnate, once-pinnate-pinnatisect, etc.

10. Examples of variously divided leaves
twice- pinnate
Petiole or stipe
simple (entire)
once-pinnate
pinnate

11. Indument: of hairs, scales, or both?

12. Sorus shape and position: round and near margin, etc.

13. Indusium: present or absent

14. Habitat: Cinnamon fern: Interrupted fern: sunnier, wetter:
shadier, not so wet:
Osmunda cinnamomea
Cinnamon fern

15. Ferns are spore-dispersed plants
Fern Life History
Ferns are spore-dispersed plants

16. The spore is one-celled, and structurally simple

17. Whereas the seed is multicellular and complex in structure
embryo
Whereas the seed is multicellular and complex in structure

19. So what happens to the spore?

20. A mature fern gametophyte

21. Archegonium
Antheridium

22. Fertilization