Pteriodophyta Flashcards
Classification and Examples
1) Psilopsida -
-Psilotum (Living fossil)
-Rhynia (fossil)
2) Lycopsida - (club moss)
-Lycopodium
-Silenginella
-Isoetes
3) Sphenopsida- (horse tail)
-Equisetum
4) Pteropsida- (fern)
-Pteridium
-Pterus
-Dryopterus
-Adiantum
-Azolla
-Salvinia
-Marcillia
-Ophyglossum
Importance of pteridophytes
Used as soil binders, ornaments, medicinal purposes
Habitat of pterido
- Cool, damp and shady places
-Some may flourish well in Sandy soil conditions
Plant Body
Sporophytic P.B.
Well differentiated roots, stem and leaf
- Root: Adventitious root
(some pterido possess rhizoids) - Stem: creeping/Ariel
Underground stem : rhizome
-Leaf - 3 types
Sporophyll : bear sporangia
Trophophyll : Photosynthetic
Scaly small dry leaf : for protection
Sporophyll form distinct compact structure called strobili/ cones in
Selanginella & Equisetum
Macrophyllous and Microphyllpus leaves are found in:
1) Macrophyllous - Ferns, basically Pteropsida group
2) Microphyllous - Selanginella(ncert), Lycopodium, Equisetum
What is heterosporous and homosporous pteridophyta? Which one is in majority?
Majority pteridophytes are homosporous:-
Homosporous: male and female gamete arise from same spore Ex.
Heterosporpus - different spores male and female gamete arise on
Ex. SIMAS (Selanginella[ncert], Isoetes, Marsilia, Azolla, Salvinia[ncert])
Points about Heterosporous Pteridophytes
- Megaspore and Microspore give rise to female and male gametophyte respectively.
- Gametophyte depend upon sporophyte and the spores germinate on the sporophyte to give rise to male and female gametophyte (Endosporic germination)
- Female gametophyte is retained on parent sporophyte for variable periods and the development of young embryo takes place within female gametophyte. This event is a precursor to seed habit
Conditions for Seed habit
- Endosporic germination
- Heterosporous germination
Seed habit started in heterosporous pteridophytes but established in gymnosperm for the first time.
Important Points
1) Haplo diplonatic life cycle
2) Show independent Alternation of Generations.
3) Reptiles of Plant Kingdom
4) Xylem lacks vessel and Phloem lacks companion cells
5) Sciophytes
6) First terrestrial plants
Why is spread of living pteridophytes restricted to narrow geographical regions?
Specific, restricted habitat requirement and need of water for fertilization.