CLASSIFYING
PLANT GROUPS
OCS Biology
Mrs. Bonifay
PLANTS
 Scientists have identified more than
260,000 kinds of plants.
 They classify plants according to whether
they have body parts such as seeds,
tubes, roots, stems, and leaves.
 The three main groups of plants are seed
plants, ferns, and mosses.
Vascular Plants
 Vascular plants have tube-like cells.
These cells form tissue called vascular
tissue. The tissue forms tubes that
transport food and water through the
plant.
 Vascular means “vessel” or “tube.”
 Seed plants and ferns are vascular
plants..
Vascular Plants
 Vascular plants have well-developed
leaves, stems, and roots.
 Because of vascular tissue, these plants
can grow larger because its leaves and
stems do not need to be near water.
 Vascular tissue is thick and provides
support for a plant. This allows the plant
to grow tall.
Nonvascular Plants
 Nonvascular plants do not have tube-like
cells.
 Mosses are nonvascular plants.
 These plants are short and must have
constant contact with moisture.
 These plants usually grow in damp,
shady places on the ground and on the
side of trees and rocks.
Seed Plants
 Seed plants are different from ferns and moss
because they use seeds to reproduce.
 A seed is a plant part that contains a beginning
plant and stored food. The beginning plant is
called an embryo.
 The seed has a seed coat which holds in
moisture.
 Seed plants have the most advanced vascular
tissue of all plants with well-developed leaves,
stems, and roots.
Seed Plants
 Seed plants come in many different sizes
and shapes. This helps them live in
many different places.
 Seed plants are the largest group of
plants. They are divided into two groups:
1. flowering plants
2. non-flowering plants
Angiosperms
 Flowering seed plants are called
angiosperms.
 A capsule, or fruit, protects the seeds of
angiosperms.
 The fruit forms from part of the flower,
which comes in many shapes and colors.
Angiosperms
 Angiosperms are divided into monocots
and dicots.
 Most angiosperms are dicots, which
contain two cotyledons (a structure in the
seed that contains food for the
developing plant).
 A bean is an example of a
large dicot seed.
Angiosperms/Dicots
 When a bean is planted, the plant
appears to have two leaves. If you split a
bean apart, you may be able to see the
two leaves in the tiny embryo.
 If you look at the leaves of a dicot plant,
the veins are branched or netlike. This is
another property of a dicot.
Angiosperms/Dicots
 Most flowering plants are dicots.
 Animals eat dicots in the form of fruits
and vegetables.
 Other examples of dicots are oak trees,
roses, sunflowers, and giant redwood
trees.
Angiosperms/Monocots
 Monocots have only one cotyledon.
 When a monocot begins to grow from a
seed, only one leaf appears. Also, the
veins in the leaf are parallel.
 Monocots include grass, corn,
wheat, rice, and flowers such
as lilies and orchids.
Gymnosperms
 Non-flowering seed plants are called
gymnosperms.
 The seeds of gymnosperms are not
surrounded by fruit. The seeds are
produced inside cones. For example,
pine trees form on the
scales of cones.
Conifers and Other
Gymnosperms
 The major group of gymnosperms is conifers, which are conebearing gymnosperms.
 All conifers are woody shrubs or trees.
 Most conifers have green leaves all year. Because of this, they
are called evergreens.
 Conifers’ leaves are shaped like needles. They do not lose water
as easily as broad leaves. They can live in dry places.
 Other gymnosperms include the ginkgo tree, which has fanshaped leaves. They are able to survive pollution better than
other trees.
Seedless Plants
 There are two main groups of seedless
plants: ferns and related plants, and
mosses and related plants.
 Ferns are vascular plants, but do not
have seeds.
 Mosses are non-vascular plants, and
also do not have seeds.
Ferns
 Like other vascular plants, ferns have welldeveloped leaves, stems, and roots.
 The ferns’ leaves, or fronds, are usually large
and flat. They are divided into leaflets that
spread out from a center rib.
 On the underside of the fronds, you can see
small dots called sori. These are clusters that
contain the reproductive cells of the fern, called
spores. When the spores are ripe, the sori
burst open and release the spores into the air.
Ferns
 The rhizome is a plant part that shoots
above ground and roots below ground.
 Fern spores that drop in a moist place,
produce a a tiny plant or rhizome.
Mosses
 Mosses are gymnosperms. They are nonvascular plants the do not have welldeveloped leaves, stems, and roots.
 They do not have vascular tissue to transport
water, so they must live in moist shady places.
 Mosses get water through root-like threads
called rhizoids.
 Like ferns, mosses reproduce by spores.
Mosses produce a great number of spores.
Soil and Bog Builders
 Mosses can grow in places where other plants cannot
root because they are so tiny.
 Mosses grow on tree bark, rocks, and in thin soil.
 When moss plants die, they form humus, which is
made from dead plants and animals, and is very rich
and helps plants grow.
 A bog is wet, spongy ground that is made from rotted
moss and other plant matter. Air does not reach the
dead plants and the lack of oxygen keeps the plants
from breaking down quickly. Over time, the plant
matter becomes tightly pressed together and forms
peat. Peat moss is used to enrich garden soil.