Sepals - Many sepals are bud
covers which protect the flower before it blooms; some help support the
petals when the flower blooms. These are often, but
not always, green in color. Some flowers, such as lilies, have sepals
that are the same color as the petals, also called "tepals". Other
flowers have only colored
sepals and no petals.
Petals - Many flowers have large,
colorful petals. Petals serve as "cafe signs" to attract pollinators.
Bees, butterflies, hummingbirds and other pollinators come to the
flowers to drink the sweet nectar. In the process of getting a meal,
they also spread pollen from one flower to another. Some petals have
special markings called nectar
guides. These markings serve as "road maps" to show the
pollinators where to find the nectar. Some nectar guides are spots or
stripes or they may be a different colored
single petal, as seen on the flame azaleas above. Wind-pollinated
flowers, such as grasses, ragweed, and many trees, do not have petals.
Wild Petunia (notice
the nectar guides on the petals)
Stamens - The male
parts of the flower, the stamens, produce pollen on the anthers. Pollen
fertilizes the ova inside the ovary to produce seeds. The staminate
flowers of wind-pollinated plants dump loads of pollen into the air to
be spread to the tiny pistils by the wind. These flowers are an allergy
sufferer's nightmare!
Pistil - The female part of the
flower is made up of the ovary, style, and stigma. To avoid
self-fertilization, many flowers have pistils that are either shorter
or
longer than the stamens. Some flowers prevent self-fertilization by
having the pollen on the anthers mature at a different time than the
stigma. The stigma is sticky
to help trap the pollen grains. Pollen grains grow a long tube down
through the style (which is several inches long in the case of corn
silks), the genetic material from the pollen travels down the tube to
the eggs. The ovaries sometimes become edible fruits such as apples,
cucumbers, corn, oranges, tomatoes, beans, etc. Not all fruits are
edible, for instance, cotton bolls are the fruits of the cotton flower.
Colors of flowers
Flowers come in many different
colors; the color of the flower often influences the type of pollinator
that visits it.
Bees are able to see ultraviolet
light,
a "color" that humans can't see. Many flowers reflect ultraviolet
light.
Some flowers have ultraviolet nectar guides, they "glow" like neon
signs
in a field.
Red and orange flowers attract
hummingbirds. Bees can't see red or orange.
Blue, yellow and white flowers attract bees
and butterflies.
Maroon flowers attract
flies
and some beetles.
Green flowers are usually,
but not always, wind pollinated.
Shapes of flowers
Coneflower with Bumblebee
Flowers come in many
different shapes, which determines what type of pollinator they attract.
Saucer or bowl-shaped flowers -
these are simple, primitive
flowers
which are usually visited by "intellectually challenged" insects such
as
beetles, wasps, and hoverflies. Examples: Roses,
poppies,
magnolias, St. Johnsworts
Bell flowers - these are
more complex flowers which are pollinated by bees. Examples: Morning
glories,
lily of the valley, chives, nasturtium, campanula
Tube flowers - these flowers
must be visited by pollinators with long tongues, such as bees,
butterflies, moths, and humming birds in order to be fertilized.
All mint flowers are tube-shaped. Examples: Mints, cardinal
flower, phlox, primroses, trumpet creeper
Pea or bean-type flowers - these flowers are considered a form
of tube flower. They always have an upper petal called a standard, a lower petal called a keel, and two petals on each side of the keel called wings. If you open the wings you
can see the stamens and pistil of the flower. These flowers are usually
visited by bees and honeybees. Examples:
Sweetpea,
clovers, alfalfa, locust, vetches, tick trefoils, kudzu,
lupines, wisteria
Composite flowers - these flowers are made up of a few to
hundreds of smaller, individual florets called "disk flowers" in the
center and the petal-like "ray flowers" around the edges. Many
composites bloom from the outside of the disk to the inside. The
individual flowers mature at different rates, so outer flowers have
mature pistils and the inner flowers have mature stamens. When a bee
visits a flower, she gets pollen on her body from the inner flowers
which she then deposits on the pistils of the next flower. Each
individual flower can make a single seed. Examples: daisies,
chicory,
fleabanes, ragweed, yarrow, pussytoes, asters, goldenrods, sunflowers,
thistles, coreopsis, coneflowers, elephant's foot, ironweed,
Joe-Pye-weed, rabbit tobacco, sneezeweeds, hawkweeds, rattlesnake
weeds, blazing
stars
Closed flowers - these flowers have such tightly
closed petals they are pollinated by only large, strong, intelligent
insects such as bumblebees which are able to force their way into them.
Examples: some
gentians,
turtlehead,
toadflax
Trap flowers - these flowers are "sneaky," they trap
insects inside them until pollination occurs. Milkweeds are
interesting flowers in that they catch insects' legs in little slits which contain the
V-shaped pollen-bearing pollinia. Some weaker insects, such as soldier
beetles, are unable to escape from the slits and they die. Examples: some orchids,
Dutchman's-pipe
Wind-pollinated flowers -
these flowers are dull colored, have no petals and produce huge amounts
of pollen. The anthers of some wind-pollinated flowers hang by thin
threads. Examples:
Ragweed,
grasses, pine and juniper trees, oak trees, many other trees
Ragweed
Flowers (Male flowers above, female flowers in leaf axils)
Cleistogomous Flowers -
Some flowers, such as violets, have closed, self-pollinating flowers.
The green pod beneath the purple bloom is a cleistogomous flower. The open
brown pod has already split and thrown its seeds.
Be sure to observe different wildflowers to see which insects or
animals pollinate them.
Seeds
Plants
have different methods of spreading their seeds:
Wind - these seeds
have parachutes or wings (called "samaras") to spread by the
wind;
examples: dandelion, maple
Animals -1. Seeds have
hooks to stick to animals' fur (or your socks); examples: cockleburs,
tick trefoils, Spanish needles, agrimony
2. Fruits are eaten and seeds pass through bird or other animals'
digestive tract; examples: dogwood, poison ivy, honeysuckle,
Jack-in-the-Pulpit
3. Seeds are buried by squirrels or birds for later consumption; examples:
acorns, walnuts
Ejection - Some plants
throw their seeds; examples: Jewelweed, geranium, witch-hazel
Life
Cycle
Annual - the plant lives only
one year; it dies in the winter, reseeds, and then new plants grow from
the seeds the following year
Perennial - the plant
overwinters and grows back from the roots the following spring; it
lives for 3 or more years
Biennial - the plant
lives 2 years, the first year as a leafy, non-blooming plant, the
second year it blooms, goes to seed, and then dies
