Download Background Information on Monocots and Dicots There are many

Background Information on Monocots and Dicots
There are many differences between the seeds, roots, stems, leaves and flowers of monocots
and dicots.
SEEDS
Monocot seeds have a protective seed coat. A monocot seed contains one cotyledon, or seed
leaf, in its embryo. Food-storing tissue called endosperm surrounds the embryo. When the
seed sprouts, the cotyledon stays below the ground. It absorbs nutrients from the endosperm
and transports the nutrients to the seedling.
A seed coat also protects a dicot seed. Inside are two cotyledons. The cotyledons absorb
and store food from the endosperm before the seed sprouts. Once the plant begins to grow,
the two cotyledons emerge from the soil. These seed leaves look different from the adult
leaves that develop later. Seeds of dicots usually can be separated into two halves, like a
peanut; those of monocots cannot.
ROOTS
Monocots have fibrous roots that spread and branch out underground. These roots anchor the
plant and provide a great deal of surface area for gathering water and minerals from the soil.
Dicots usually have one long, thick root called a taproot. Small secondary roots grow from
the taproot. The length and strength of the taproot can make a dicot plant difficult to pull out
of the ground.
STEMS
Stems contain tubes that carry food downward and water and minerals upward in the plant.
In monocots, these tubes are scattered throughout the stems in no particular pattern. In
dicots, the tubes are arranged in a ring around the center of the plant stem. This ring is
visible just within the outer edge of a traditional potato chip. The part of the potato that we
eat is considered an underground stem. This is also why roots form when a potato sits in
water for a period of time.
LEAVES
Leaves of monocots have parallel veins. In the leaves of dicots, the veins intersect inside the
leaf, forming a branching pattern.
FLOWERS
Monocots usually have flower parts that are in multiples of three. Lilies, for example, are
monocots with flowers that have three petals, three sepals, and six stamens. The flowers of
dicots are more varied. They have parts that are usually in multiples of two, four or five.
EXAMPLES:
Monocot seeds include grasses, such as corn and rye, and grains, such as rice and wheat.
Dicot seeds include bean, peanuts, peas, apples, broccoli, and just about everything you
grow in a garden. They also include the seeds of most shrubs and trees.
Background Information on Gymnosperms and Angiosperms
GYMNOSPERMS
Gymnosperms are the most ancient group of seed plants. They first appeared about 360
million years ago—about the same time as the first land animals. Gymnosperms are the
non-flowering seed plants such as cedar, pine, redwood, hemlock, and firs. Gymnosperms
are woody plants that bear "naked seeds." They are called naked because their seeds develop
exposed on the upper surfaces of cone scales, such as in pinecones. A pollen grain is carried
by wind to the egg where the growth of the pollen tubes brings the sperm to the egg. The
female cones produce the eggs, or ovules. Female cones have a sticky resin that “catches”
the pollen released by the male cone. When fertilized, the female cone enlarges and the
scales separate. This separation allows the seeds to drop out of the cone, where they mainly
rely on the wind, or animals on the ground (chipmunks, squirrels, etc.) to scatter them. Pine
trees and other gymnosperms produce two types of cones. The male cone is called the pollen
cone. The larger female cone is the seed cone. A single tree usually produces both pollen and
seed cones. Gymnosperms are usually large in size and their leaves are needles or
scales. When it comes to their life cycle, they are found to stay alive and green all
throughout the year.
ANGIOSPERMS
Angiosperms have flowers and bear seeds enclosed in a protective covering called a fruit.
Angiosperms are the dominant types of plants today. Angiosperms are further divided into
monocots and dicots (read more about these on the other side!). There are at least 250,000
species of angiosperms ranging from small flowers to enormous wood trees. Angiosperms
can be found in just about all of Earth’s environments, including frozen wastelands near the
North Pole, steamy tropical jungles, and practically waterless deserts. The wind, insects, and
other animals accomplish pollination. The male part is the pollen grain, and the female part
is the ovary. The ovary contains eggs, or ovules, which are then fertilized by the sperm
contained in the pollen. The sperm of the male part travels down the pollen tube in the style.
After the process of fertilization (sperm and egg meeting), the egg turns into a seed with an
embryo. The seed is contained inside of the growing ovary, now called a fruit. In
angiosperms, the pistil is the female reproductive structure found in flowers, and consists of
the stigma, style, and ovary. The stamen is the male reproductive structure of a flower;
usually consisting of slender, thread-like filaments topped by anthers, which contain the
pollen. The angiosperms normally die during the season of autumn.