Reading: Diagram Label Completion: Question 2

Beneath the bright colours that attract pollinating insects, a flower is a highly organised reproductive structure in which every part occupies a precise position for a functional reason. At the base of the flower, the stalk widens into a small swelling called the receptacle, from which all of the flower's other parts grow in a series of concentric rings.

The outermost ring consists of small, often green, leaf-like structures called sepals, which enclose and protect the developing bud before it opens; together the sepals are known as the calyx. Just inside the sepals sits the next ring, the petals, whose colour, scent and shape have evolved primarily to attract pollinators such as bees and moths rather than to serve any structural role.

Moving further inward, the third ring is made up of the male reproductive organs, the stamens. Each stamen consists of a slender stalk, the filament, topped by a swollen structure called the anther, inside which pollen grains are produced. When an insect brushes against the anther while feeding, pollen grains stick to its body and may later be carried to another flower.

At the very centre of the flower lies the female reproductive structure, the carpel. The carpel's uppermost part, the stigma, is often sticky or feathery so that pollen grains landing on it will adhere rather than fall away. Below the stigma runs a narrow tube-like section called the style, which connects the stigma to the swollen base of the carpel, the ovary, where the ovules that will develop into seeds are contained. Small glands located near the base of the petals, called nectaries, produce the sugary liquid that rewards visiting insects for transferring pollen between flowers.

The diagram below shows a vertical cross-section through the centre of a flower, arranged from the outer edge of the flower inward to its centre, and from the base of the flower upward to the tip of the central carpel.

Label the diagram below. Choose NO MORE THAN TWO WORDS from the passage for each answer.

1. the small swelling at the base of the flower stalk, from which all the other parts grow
2. the outermost ring of small, leaf-like structures enclosing the unopened bud
3. the ring of parts just inside the outermost ring, coloured to attract pollinators
4. the slender stalk at the base of a male reproductive organ
5. the swollen structure at the top of that slender stalk, where pollen is produced
6. the sticky or feathery structure at the very top of the central female organ
7. the narrow tube connecting the top of the central female organ to its swollen base
8. the swollen base of the central female organ, containing the seed-forming structures