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 arefemale 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