1. Gymnosperms

2. Gymnosperms Similar to angiosperms in that they produce a seed
All gymnosperms (an angiosperms) are considered heterosporous
Produce two types of spores: microspores and megaspores
Gymnosperm means “naked seed” in greek meaning seeds are totally exposed or borne on the scales of female cones
Examples: pine, spruce, fir, hemlock, ginkgo

3. Unique Gymnosperms
This category includes some of the most interesting plants including giant sequoias, redwood trees, and bristlecone pines

4. Four phyla Coniferophyta Ginkgophyta Cycadophyta Gnetophyta
Each has unique characteristics so let’s look at them closer!

5. Conifers About 630 species Most familiar group
All conifers are woody trees that produce annual additions of tissue (annual rings)
Produce resin
a viscous, clear or translucent substance consisting of organic compounds. Helps protect plant from fungal or insect attack

6. Conifers
Most conifer leaves are called needles that can be found in clusters or individually depending on the type of conifer
Some leaves are scale like and cover the stem

7. Conifers
Most conifers are evergreen meaning their leaves remain throughout the year
Most conifers are monoecious meaning they have separate male and female reproductive parts in different locations on the same plant. Pares are found in the strobili or cone

8. Conifer Reproduction Female cones larger than male cones.
1. When a female cone is mature, it will open to allow the megasporangia to be exposed.
2. Male cones produce microspores that develop into pollen grains that are dispersed by the wind.
3. Pollen lands on exposed megasporangia producing seeds with papery wings to be dispersed for a new plant.

10. Cycads
Most significant during the triassic period. Most species are extinct, but the ones that remain are tropical and subtropical plants
Popular as ornamentals, therefore many species endangered

11. Ginkgo Only contains one living species: the ginkgo or maidenhair tree
Named because of fan-shaped leaves resembling the maidenhair fern
Oldest genus and species of living trees. Found to be at least 170 million years old
Female ginkgo trees release a smell when the seeds mature therefore, some cities have ordinances against the planting of female trees because of their stench

12. Gnetophytes
Contain more efficient water conducting cells in their xylem called vessel elements
Cone clusters resemble flower clusters
Some have seeds that are fleshy and resemble fruits from flowering plants

13. Ecological and Economic Importance
Conifer forests provide stabilization of soil
Trees used for christmas trees, timber, medicinal products, resins, and varnishes