1. Seed Plants
Seed = embryo sporophyte, encased in and dispersed with gametophytic and maternal sporophytic tissues.
Gymnosperms – seeds “naked” in cones
Angiosperms – the flowering plants
seeds enclosed in carpels
carpel = modified leaf fused around seeds; becomes fruit

3. Gymnosperms – 4 Phyla
Cycadophyta – the cycads. Superficial resemblance to palms, but have cones
true palms have flowers & fruits like dates or coconuts
Ginkgophyta –1 living species, Ginkgo biloba
Gnetophyta – Strange group; classification unsure
Coniferophyta – the conifers: pine, spruce, fir, cedar, redwood, cypress, etc.

5. Highly reduced gametophytes
Male gametophyte is the pollen grain.
In gymnosperms, it consists of about 4 cells.
One of these is the sperm nucleus.
Whole gametophyte is dispersed by wind.
No motile cells.

6. Ovule
Immature seed
Female gametophyte (megagametophyte) consisting of about 1000 cells.
Surrounded by Integuments - layers of maternal sporophytic tissue.
Opening in the integuments, called the micropyle, allows sperm access to eggs.

7. Figure 29.5 The Life Cycle of a Pine Tree
Seed cone
Scale of seed cone
Section through scale
Functional megaspore
HAPLOID (n)
Gametophyte
generation
Meiosis
Megasporangium
Ovule
Pollen
chamber
Female
gametopyte
Pollen cones
Micropyle
Female
gametopyte
Reduced
archegonium
Microspore
mother cells
Egg
Microspores
Section
through
scale
Sporophyte
Scale of
pollen
cone
Male gametophyte
(germinating pollen
grain)
Pollen grain
Fertilization
Seed coat
Female
gametophyte
Zygotes
Embryo
Female
gametophyte
Seed cone
Seed
Suspensors
Winged seed
DIPLOID (2n)
Sporophyte
generation
Wing
Developing embryo
Scale of seed cone

8. Figure 29.5 The Life Cycle of a Pine Tree

9. The Flowering Plants The phylum Angiospermae
(also known as Anthophyta or Magnoliophyta)
Most numerous living plant group (250,000 spp.)
(only ~750 species of gymnosperms, 12,000 ferns)
Characteristic features:
Ovules and pollen produced in flowers.
Ovules contained inside carpels.
Double fertilization forming triploid endosperm.

10. Carpel (Pistil)
Stamen

12. Ovules within carpels
Seeds within fruits.

13. Angiosperm gametophytes
Highly reduced.
Male gametophyte (microgametophyte) is pollen grain with 3 haploid nuclei.
Female gametophyte (megagametophyte) is 8 nuclei inside the ovule.
One of the 8 is the egg cell.
Two are “polar nuclei” and are important in double fertilization.

14. Figure 29.10 The Life Cycle of an Angiosperm
Stigma
DIPLOID (n)
Carpel
Style
Anther
Ovary
Stamen
Filament
Ovule
Megaspore
mother cell (2n)
Microspore mother cell (2n)
Endosperm
nucleus (3n)
Meiosis
Meiosis
Surviving
megaspore (n)
Zygote (2n)
Pollen grain
(microgametophyte, n)
Double Fertilization
Megagametophyte (n) with 8 haploid nuclei
Megagametophyte
Tube cell nucleus
Sperm (n)
Pollen
tube
HAPLOID (n)

15. Double Fertilization
One sperm nucleus fertilizes the egg, forming a zygote, which grows into an embryo (as you would expect).
Another sperm nucleus fuses with the two polar nuclei, forming a triploid cell. This divides by mitosis to form a triploid tissue called endosperm. Endosperm acts as a nutritive tissue for the developing embryo.
For more detail, see pp

17. Angiosperm groups Primitive angiosperms: Monocots: Eudicots:
No vessels in wood; No fusion of carpels.
Monocots:
One embryo leaf; parallel veins in leaves; flower parts in multiples of 3
Eudicots:
Two embryo leaves; netted veins in leaves; flower parts in multiples of 4 or 5.