Presentation on theme: "Flowers HortBotany Lesson Plan #9. Flowers: A Marvelous Innovation Flowering plants first appeared around 140 million years ago (Upper Jurassic). Oldest."— Presentation transcript:
Flowers HortBotany Lesson Plan #9
Flowers: A Marvelous Innovation Flowering plants first appeared around 140 million years ago (Upper Jurassic). Oldest flower fossil is 125 million years old. The dominant forms of plant life were gymnosperms, cycads, and ferns.
Today Flowering plants (Angiosperms) are now the dominant form of plant life over most of the earths land surface. Ferns are rarely dominant and gymnosperms are dominant only in cold, or seasonally cold locations. Cycads are hanging on by a thread. Why have flowering plants been so successful?
Angiosperm Flowers Ovaries protect ovules and developing seeds; mature into fruits that promote seed dispersal Floral structure encourages pollinator fidelity; nectar and pollen to reward pollinators Fast reproductive cycle compared to gymnosperms
Structure of flowers Flowers are composed of four whorls. From the outside in, they are: Calyx (sepals) Corolla (petals) Androecium (stamens) Gynoecium (pistils)
Calyx Outermost whorl Usually green Protects developing flower Made up of SEPALS Sepals free or not
Sepals Usually green; leaflike structures that protect the flower, as it forms and emerges.
Sometimes sepals are colorful
Calyx The group of sepals on a flower
Corolla Is usually colorful and showy Attracts pollinators Guides pollinators Is composed of petals Petals may be united or separate
Petals Located just inside the sepals Leaf-like and often very colorful
Corolla The collection of petals on a flower
Perianth The sepals and the petals of a flower. (Not the reproductive parts.)
Tepals When there is no clear distinction between the sepals and the petals...they are called tepals. HIPPEASTRUM 'MARMADUKE
Androecium Is composed of stamens Stamens have filaments and anthers Pollen is produced in anthers Stamens can be free or united
Stamens Male reproductive parts of a flower Arranged around the female parts
Anther Part of the stamen Produces and holds pollen
Filament Stalk that holds up the anther
Gynoecium Is composed of pistils A pistil is composed of an ovary, style, and stigma.
Pistil = 1 or more carpels Each theoretical leaf unit is termed a carpel A pea pod is a mature pistil made up of 1 carpel Pistils with 2 style branches and/or chambers in the ovary are said to have 2 carpels Pistils with 3 style branches and/or chambers are said to have 3 carpels etc.
Stigma Found at the end of the pistil Has a sticky surface to catch pollen
Style The neck of the pistil
Ovary Part of the pistil that contains the ovules
Ovule The part of the flower in which the eggs are produced and seeds develop
Ovary Position I. Above the calyx and corolla (ovary superior) II. Ovary partially inferior III. Below the calyx and corolla (ovary inferior) Ovary position: I superior II partially-inferior III inferior. a androecium g gynoecium p petals s sepals r receptacle.
Hypanthium If the corolla and calyx are attached to a cup or tube that is then attached to the receptacle, the cup or tube is called a hypanthium.
Receptacle The top floral whorls are attached to the receptacle – the tissue where the stalk to the flower changes to being part of the flower
Pedicels Flowers are borne on pedicels Think of a pedicel as the stalk to a flower
Attracting Pollinators To survive, species must reproduce Pollination is the first major step in the reproduction of seed plants like gymnosperms and angiosperms Flowers persuade animals to serve as pollinators, preferably faithful pollinators To get the right pollen, flowers need to be memorable so …
Start thinking like a pollinator Is there a reward? How can I find another like this one? –Symmetry –Color pattern –Odor Will it be safe for me? –Corolla – united or separate petals –Corolla more important than calyx – why? Can I reach the reward and is it adequate? –nectaries and androecium
wind pollination; eastern cottonwood catkins
Complete vs. Incomplete Flowers
Complete flowers Have all 4 basic parts: Sepals, petals, stamens and pistil
Incomplete Flowers Flowers that are missing one of the four basic parts
Perfect vs. Imperfect Flowers
Perfect Flowers Flowers that have both male and female parts
Imperfect flowers Flowers that lack one of the sex structures
Monoecious vs. Dioecious
Monoecious = 1 House refers to a species separate male and female flowers on the same plant Black Alder male catkins and female strobili
Dioecious = 2 Houses refers to a species separate male and female flowers on different plants
Common Winterberry male flowers Common Winterberry female flowers Common Winterberry fruit