1. The Gymnosperms Sporophyte dominant
seed plants that do not form flowers but cones
xylem consists of tracheids (except Gnetophyta)
undergo secondary growth
Produce soft wood
Known as evergreen plants or conifers
gymnos-, means “naked”, -
seeds borne naked/exposed on megasporophylls arranged in female cones
Seed with endosperm which is remains of female prothallus,
Endosperm haploid
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2. Gymnosperms…
microspores produced microsporangia on microsporophylls arranged in male cones
No Flowers; most wind pollinated
plants always heterosporous
megaspores produced in female cones
gametophytes very reduced
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3. Classification 4 groups recognised Cycadophyta – cycads
Ginkgophyta – Ginkgo
Gnetophyta – gnetophytes
Coniferophyta – conifers
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4. Cycadophyta Large, palm-like plants with frond-like leaves
Tropical or subtropical
Mostly dioecious
dominated the earth some 2000m yrs ago at the same time as dinosaurs
Trees grow very slowly (2m tree =1000 yrs)
Possess flagellated sperms (primitive feature)
Examples: Cycas and Zamia
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5. Cycads: Encephalartos sp and Cycas sp (female plants)
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6. Cycas sp- female plant
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7. Ginkgophyta one living member, Ginkgo biloba
deciduous tree with bilobed, fan-shaped leaves
No female cones- ovules naked
seeds produced naked on branches
Cultivated as ornamental plant in urban parks etc
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8. Ginkgo biloba
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9. Gnetophyta Have angiosperm-like features Contain vessels in xylem
Pollen producing structures superficially resemble stamens
Some lack archegonia (Gnetum and Welwitschia)
Examples include Welwitschia (the desert octopus), Gnetum and Ephedra
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10. Gnetophyta Welwitschia mirabilis
A xerophyte in southern Africa (Namib desert)
Above ground stem consists of two long, strap-like leaves that creep along soil surface
Leaves tough and leathery with sunken stomata
Exceptionally large storage tap roots
Well adapted to arid habitats
Plants lives long yrs!
Attracts many tourists!
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11. Welwistchia mirabilis- plant habit, male and female cones
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12. Coniferophyta Tall trees with needle-like leaves
Found in cold temperate and subtropical habitats
Highly adapted to dry and windy conditions.
To conserve water they have:
needle-like leaves
sunken stomata
thick cuticles.
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13. Conifers… Adaptations to windy environments include: wind pollination
seed dispersal (winged seeds)
Mostly monoecious,
male (staminate, pollen) cones
female (ovulate, seed) cones (eg Pinus)
Most economically important gymnosperms
Paper making
soft timber for furniture manufacturing, building, household items
Examples are Pinus, Cupressus, Juniperus,etc
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14. Coniferophyta- Pinus sp female cones
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15. Pinus female cones- scales open, seeds released
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16. Pinus male cones
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17. Pinus – male cones- shedding pollen; wind pollination
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18. Pinus pollen- winged pollen for wind pollination
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