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Adding Value To The Business of Cropping

Flower facts

Learning Intentions:

    Students will be able to:
  • name and state the functions of the main parts of a flower
  • describe what pollination is
  • state differences between animal and wind pollinated flowers and give examples of each.

The main parts of a flower

Flower parts

  • Sepals enclose the flower buds.They split open and fold back so the petals can open.
  • Petals enclose the reproductive structures. In insect pollinated flowers, these are usually coloured and easily seen so they attract insect and bird visitors. The petals usually have to open before pollination can occur.
  • Anthers produce the pollen. Anthers are usually at the end of a filament. An anther and its filament are referred to as a stamen and are the male parts of a flower. The anthers must open or split to release the pollen.
  • Pollen grains contain the male genetic material that must be moved to the female reproductive structures for fertilisation to occur.
  • Stigmas are at the end of a pistil. They are the female structures that the pollen sticks to.
  • The Ovary is normally at the base of a flower and contains from one to many ovules.
  • Ovules are the female structures that must be fertilised to produce seeds.
  • Nectaries produce nectar to attract animal visitors. These are usually found at the base of the petals.

Pollen, ovules and seeds

Plants usually produce a small number of ovules, but millions of pollen grains. 

To produce a seed, pollen must be moved from an anther to the stigma of the same type of flower. This is process is called pollination.

Depending on the plant species, the pollen may have to be moved a few millimetres or many metres, either by animals such as insects, or the wind.  

Once on the stigma the pollen grain produces a pollen tube that grows down inside the pistil to reach an ovule and achieve fertilisation. The ovule then grows into a seed. 

Differences between insect and wind pollinated flowers

Structure

Insect pollinated

Wind pollinated

FlowersUsually conspicuous* and often largeInconspicuous*, often dull and small
PetalsOften large and brightly colouredDull and small
PollenHeavy and sometimes stickyLight
StamenNear entrance to flower Positioned high on the plants and dangle outside flower 
StigmaSticky and near entrance to flowerLarge and feathery 
NectarMakes nectarNone
ScentUsually scented*Unscented*


* Meanings of words in table

Conspicuous: easily seen.
Inconspicuous: not easily seen.
Scented: smells (usually nice).
Unscented: no smell.

Method of pollination

Flowers pollinated by animals
(insects and birds) examples

Flowers pollinated by wind
examples

  • Cabbage
  • Broccoli
  • Parsnip
  • Carrot
  • Beans
  • Peas
  • Pumpkin
  • Squash
  • Sunflower
  • Harakeke / New Zealand flax
  • Mānuka
  • Pōhutukawa
  • Rātā
  • Kōwhai
  • Corn
  • Maize
  • Wheat
  • Oats
  • Barley
  • Rice
  • Toetoe
  • Pampus
  • Ryegrass
  • Tawai / Silver beech
  • Haumata / Tussock
  • Walnut
  • Oaks
  • Pines

Resources


Related resources

Flower dissection activity sheet

Secret flowers

Picture credits: Thumbnail diagram and Parts of Flower diagram (Pixy.org).