20.2 Classification of...
Transcript of 20.2 Classification of...
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