EX.11 - Flowers

• EXPERIMENT 11
• The flower is small and closed within itself.
• A flower is the reproductive part of a plant and its function is to mediate the union of male sperm with female ovum in order to produce seeds.
• Pollination/reproduction is a process in which the pollen grains from the flower anther are transferred to the stigma.
• Fertilization is a process of fusion of the pollen grains with the ovum to form the zygote.
• The accessory parts of a flower, also known as vegetative whorls, are not involved in the reproductive process and the peduncle or pedicel swells at its tip into a small pad known as recepacle.
• The outermost whorl of a flower typically consists of three to five small, usually green, somewhat lead-like sepals.
• The collective term for all the sepals of a flower is calyx.
• The petals of a flower collectively are known as the corolla.
• Perianth is the outer part of a flower.
• The stamens of a flower are the male reproductive part of the flower, made up of filament and an anther, which produces the pollen.
• The pistils of a flower are the female reproductive part of a flower, which produces ovules which are the female reproductive egg cells.
• The style of a flower is a tube on top of the ovary, it allows pollen grain to travel from stigma to ovule.
• The stigma of a flower receives the male pollen grains during fertilization.
• Flowers can be classified based on the presence of accessory parts into complete and incomplete.
• Flowers can also be classified based on the presence of essential parts into perfect, imperfect, pistillate, and staminate.
• Monoecious flowers have male and female flowers in separate structures on the same plant.
• Dioecious flowers have male and female flowers on different plants.
• Polygamous flowers have male and female in the same flower on the same plant.
• Hypohgynous flowers have a superior ovary.
• Perigynous: with a half-inferior ovary.
• Epigynous: with an inferior ovary.
• Regular: wheel-like form or radially symmetric flower.
• Irregular: form which can be divided into two equal halves.
• Catkin: spike with only pistillate or staminate flowers.
• Composite or Head: daisy-type flower composed of ray flowers around the edge and disc flowers that develop into seed in center of the flat head.
• Corymb: stemlets arranged along main stem.
• Outer florets have longer pedicals than inner florets giving the display a flat top.
• Cyme: determinate, flat or convex flower, with inner floret opening first.
• Panicle: indeterminate flower with repeated branching.
• It can be made up of racemes, spikes, corymbs, or umbels.
• Raceme: modification of a spike with flowers attached to a main stem by stemlets.
• Solitary (or single): one flower per stem.
• Spadix: showy part is a bract or spathe, partially surrounding the male and female flowers inside.
• Spike: flowers attached to main stem, without stemlets, bottom florets open first.
• Umbel: florets with stemlets attached to main stem at one central point, forming a flat or rounded top.
• Self-pollination: the process occurs when the pollen grains from the anther is deposited on the stigma of the same flower, or another flower on the same plant.
• Cross-pollination: this process occurs when the pollen grains are transferred from the anther of one flower into the stigma of another flower of different plant of the same species.
• Wind Pollinated: petals are small, inconspicuous and sometimes absent, if present, they are not brightly colored.
• Scent: none.