20.2 Classification of Plants

KEY CONCEPT Plants can be classified into nine phyla.

20.2 Classification of Plants

Mosses and their relatives are seedless nonvascular plants.• Nonvascular plants grow

close to the ground to absorb water and nutrients.

• Liverworts belong to phylum Hepatophyta.– often grow on wet rocks

or in greenhouses

20.2 Classification of Plants

• Hornworts belong to phylum Anthocerophyta. – found in tropical forests and along streams

– flat, lobed body with little green “horns”

20.2 Classification of Plants

• Mosses belong to phylum Bryophyta.

– most common seedless nonvascular plants

20.2 Classification of Plants

Club mosses and ferns are seedless vascular plants.• A vascular system allows club mosses and ferns to grow

higher off the ground.• Club mosses belong to phylum Lycophyta.

– oldest living group of vascular plants

20.2 Classification of Plants

• Ferns and their relatives belong to phylum Pterophyta.

frond

fiddlehead

– ferns have large leaves called fronds

20.2 Classification of Plants

Seed plants include cone-bearing plants and flowering plants.• Seed plants have several advantages over their seedless

ancestors. – can reproduce

without free-standing water, via pollination

– seeds nourish and protect plant embryo

– seeds allow plants to disperse to new places

20.2 Classification of Plants

• Gymnosperms do not have seeds enclosed in fruit. – most gymnosperms are cone-bearing and evergreen.– the cone is reproductive structure of most

gymnosperms.– pollen is produced

in male cones.– eggs are produced

in female cones.– seeds develop on

scales of female cones.

20.2 Classification of Plants

• Cycads are gymnosperms in phylum Cycadophyta.– look like palm trees with large cones– grow in tropical areas

20.2 Classification of Plants

• Ginkgos are gymnosperms in phylum Ginkgophyta.– only one species alive today, Ginkgo biloba– grown in gardens and used in urban landscaping

20.2 Classification of Plants

• Conifers are gymnosperms in phylum Coniferophyta.– most common

gymnosperms alive today

– includes pines, spruce, cedar, fir, and juniper

20.2 Classification of Plants

• Angiosperms have seeds enclosed in some type of fruit. – A flower is the reproductive structure of angiosperms.– A fruit is a mature ovary of a flower.

• Angiosperms, or flowering plants, belong in phylum Anthophyta.