Pterophyta

Outline

Introduction

diverse: > 11,000 spp

most ferns...

• are homosporous (a few are hetero-)
• have siphonosteles (some with proto-, eu-)

megaphyll line

Morphology (of sporophyte)

below-ground

rhizome (an underground stem)

adventitious roots

above-ground

fronds (= leaves )

• composed of petiole and blade

  blade is typically compound

  fronds may bear spores

  • spore-bearing fronds = sporophylls (may be specialized and non-photosynthetic)
  • spores are produced by clusters of sporangia called sori

Life cycle

1. sporophyte with sporophylls bearing sporangia produces spores (detect a theme here?)
2. spores germinate into gametophyte (= prothallus)
3. gametophyte (= prothallus) bears gametes in archegonia (eggs) and antheridia (sperm)
4. gametes fuse to form zygote, which develops into an embryo
5. start over at #1

Diversity

eusporangiate ferns

• e.g., Ophioglossales -- Adder's tongue fern, and Marratiales -- grape ferns
• have eusporangia
• are homosporous
• have a Psilotum-like gametophyte

Filicinales

• e.g., most ferns
• have leptosporangia
• are homosporous

water ferns

• e.g., the Salviniales: Azolla and Salvinia, and the Marsileales: Marsilea (water clover)
• have leptosporangia
• are heterosporous
• are aquatic

Vocabulary

click here to go to Pterophyta vocabulary