Seed Plants Flashcards
Cambiums
or lateral meristems, adds thickness to a plants body
Cambiums
or lateral meristems, adds thickness to a plants body
Cambiums
or lateral meristems, adds thickness to a plants body
bifacial Cambium
two faced
- cambium produces cells to the inside and outside
- inside = secondary sylem aka wood (conducts water)
- outside = secondary phloem (conducts food)
Progymnosperms
extint relatives of seed plants (didn’t produce seeds)
Homosporous and heterosporous forms
Lignophyte trends in evolution
- prosteles - homosporous, simple leaf-like structures, free sporing
- eusteles, heterosporous, simple leaves, free sporing
- eusteles, heterousporous, various leaf forms, seeds
Progymnosperms
- Archaeopteris
- heterosporous but didnt produce seeds
- branching systems looked similar to fern fronds
- eustele
- the stem produced wood
Seed Plants
Include:
- angiosperms (flower plants)
- gymnosperms (no flowers)
*** gymnosperms evolved first
Gymnosperms
- “naked seed” plants
- seeds are not enclosed in an ovary (fruit)
- no flowers ( reproductive structures usually cones)
Four living gymnosperm groups
- conifers
- cycads
- ginkgo
- gnetophytes
Extint diversity
Pteriodsperms
Cycadeoids or Bennettiatales
Cordaites
Pteridosperms
seed ferns ( seed plants with fern-like leaves)
Cycadeoids
cycad-like forms (probs not related to cycads)
Cordaites
ancestors to conifers
What is a seed?
Mature ovule with embryo
Pollen grain
microgametophyte that develops in the microspore wall
Pollination
Pollen transferred to the ovule
If sperm not flagellated
delivered to the egg by a pollen tube
in gymnosperms with flagellated sperm
the pollen tube is haustorial
Haustorial
grows into and absorbs nutrients from nucellus of ovule
bifacial Cambium
two faced
- cambium produces cells to the inside and outside
- inside = secondary sylem aka wood (conducts water)
- outside = secondary phloem (conducts food)