Gymnosperms

Dominant phase

Sporophyte

Gametophytes

Heterosporous, endosporic, unisexual

Male gametophyte

Pollen grain

Female gametophyte

Ovule

Monoecious

Male/female parts on same plant

Dioecious

Separate male/female plants

Gymnosperm divisions

Coniferophyta, Cycadophyta, Ginkgophyta, Gnetophyta

Conifer leaves

Needles (1-2 veins) or scales (several veins)

Conifer wood

Tracheids, no vessels

Long shoots (conifers)

Contain small, papery leaves

Short shoots (conifers)

Grow from axils of papery leaves; contain needles

Xeric adaptations (conifers)

Thick cuticle, sunken stomata, cylindrical leaves

Conifer mating type

Usually monoecious

Male cones (conifers)

Microsporangia, microspores, pollen

Pollen cells (conifers)

2 prothalial, 1 generative, 1 tube

Female cones (conifers)

Megasporangia, megaspores, ovules

Integument (conifers)

Surrounds ovule; produces seed coat

Pollen tube germinates

Shortly after pollination

Meiosis of megaspore mother cells

Month after pollination; requires 6 months

Generative cell divides

Year after pollination; forms sterile and spermatogenous cells

Spermatogenous cell divides

Produces two sperm (one survives)

Pollen tube reaches egg

15 months after pollination; sperm fertilizes egg

Seed matures

Two years after pollination

Cycad leaves

Pinnately compound; top of stem

Cycad pollination

Wind or insects; pollination droplet

Cycad mating type

Dioecious

Ginkgo species

Ginkgo biloba

Long shoots (Ginkgo)

Bear bifurcated leaves and short shoots

Short shoots (Ginkgo)

Bear entire leaves and cones

Ginkgo mating type

Dioecious

Male cones (Ginkgo)

Resemble catkins; two microsporangia per microsporophyll

Ginkgo pollination

Wind; pollination droplet

Female cones (Gingko)

Two ovules per stalk; droplet from micropyle; become fruit-like

Gnetophyte genera

Gnetum, Ephedra, Welwitschia

Gnetum anatomy

Vines, shrubs, or trees

Gnetum leaves

Broad, simple, opposite

Gnetum seeds

Bright, fruit-like envelope

Ephedra anatomy

Shrubs/vines, green stems, scale-like leaves

Ephedra habitat

Deserts worldwide

Ephedra names

Mormon’s tea, joint plant, joint fir

Ephedra medicinal uses

Digestion, headaches, burns, meth

Welwitschia species

Welwitschia mirabilis

Welwitschia anatomy

Long taproot, short stem, two leaves

Welwitschia mating type

Dioecious