Gymnosperms- Chapter 18

Naked versus Enclosed Seed Plants

• Gymnosperms

– Gymno- gr. naked.

– Sperma- gr. seed.

• Angiosperms

– Angeion- gr. vessel.

– Sperma- gr. seed.

Extant Gymnosperms

• Match the common name on the right to the

phylum on the left.

– 1) Cycadophyta a. ginkgo

– 2) Ginkgophyta b. conifers

– 3) Coniferophyta c. cycads

– 4) Gnetophyta d. gnetophytes

Cycadophyta

• Cycas- gr. palm.

• Tracheids, but no vessel elements.

• Sperm present, multiflagellated.

• Palmlike leaves.

• Pollen tube does not fuse with the egg cell.

• Ovulate (megasporangiate) & microsporangiate cones simple & on separate plants.

• 11 genera & 140 species.

• Examples- Cycas & Zamia.

Zamia

Cycas

Ginkgophyta

• Yin- ch. silver, hing- ch. apricot.

• Tracheids, but no vessel elements.

• Sperm present, multiflagellated.

• Fan-shaped leaves.

• Pollen tube does not fuse with the egg cell.

• Ovulate & microsporangiate cones on separate plants; fleshy-coated seeds.

• 1 genus & 1 species.

• Examples- Gingko biloba= maidenhair tree.

Coniferophyta

• Con- gr. cone, fer- L. bear.

• Tracheids, but no vessel elements.

• Sperm not motile.

• Needlelike or scalelike leaves.

• Pollen tube fuses with egg cell.

• Ovulate & microsporangiate cones on same plant; ovulate cones compound.

• 70 genera & 630 species.

• Examples- Pinus, Picea, Juniperus, Abies, Cupressus.

True or False. These winglike structures are

female pollen grains.-------------------------->

Pinus- pine (Pinaceae).

Metasequoia- Dawn redwood.

Wollemia nobilis- Wollemi pine.

Gnetophyta

• Gneto- Malay gnenom.

• Tracheids and vessel elements.

• Sperm not motile.

• Scalelike, leaflike, broad and leathery leaves.

• Pollen tube fuses with egg cell.

• Ovulate & microsporangiate cones compound & mostly borne on separate plants.

• 3 genera & 70 species.

• Examples- Gnetum, Ephedra, Welwitschia.

Gnetum

Ephedra

Welwitschia