This topic asks you to name flower structures from their jobs, define pollination, and infer whether a flower uses insects or wind. A function-first method is safer than trying to recall a labelled diagram all at once.
Follow pollen from production to reception
Start at the male part. A stamen consists of a pollen-producing anther held by a filament. Then trace pollen to the female part, which has a stigma at the top, a style beneath it and a base chamber containing ovules. Pollination ends when pollen reaches a stigma. Fertilisation is later, when a nucleus from pollen joins a nucleus in an ovule, so arrival does not guarantee that union will occur.
| Need | Feature pattern |
|---|---|
| Attract an insect carrier | Large coloured petals, scent and nectar advertise a reward. |
| Transfer pollen by contact | Pollen and the receiving surface are suited to sticking, and both are positioned where a visitor brushes them. |
| Release pollen into moving air | Exposed anthers and abundant light, smooth pollen improve the chance of transport. |
| Catch airborne pollen | A large feathery stigma projects into the airflow. |
| Avoid spending resources on animal signals | Wind-pollinated flowers have small dull petals or none and usually offer no nectar. |
For an unfamiliar flower, ask what carrier each feature fits. Showy petals and nectar make sense only if a visiting animal must be attracted. Structures hanging into the air make sense when air is the carrier. Wind transport is untargeted, so the plant releases many grains because only a small proportion will reach a suitable stigma. Cross-pollination still occurs within one species: it moves pollen between separate plants of that species, whereas self-pollination stays within one plant.
Avoid these flower mix-ups
| Tempting idea | How to reject it |
|---|---|
| Using the stigma as the place where pollen is made | Separate manufacture from reception. The anther releases pollen; the stigma is the landing surface. |
| Placing ovules on the stigma, beside pollen in the anther, or at a petal base | Trace the female structure downwards: its chamber at the base encloses the ovules. |
| Pairing stamen with stigma because the names look alike | Rebuild the male part by function: the filament supports the anther that produces pollen. |
| Saying nectar feeds a developing seed | Nectar is an external reward that draws a pollinating animal into contact with the flower. |
| Defining cross-pollination as movement between different species | Cross refers to separate plants, not separate species. Successful transfer is between plants of the same species. |
Try it
An insect-pollinated flower has to load pollen onto a visitor and then catch it again on the next flower. Which combination of features does that?
- Smooth light pollen, with a feathery stigma hanging outside the flower
- Sticky pollen, with a feathery stigma hanging outside the flower
- Sticky or spiky pollen, with a sticky stigma held inside the flower
- Smooth light pollen, with a sticky stigma held inside the flower
Wind-pollinated plants release enormous quantities of pollen. Which explanation of that quantity is correct?
- Every grain becomes a seed, so more grains means more seeds
- The extra grains feed the insects that visit the flower
- Wind pollen is heavy, so most of it drops straight to the ground
- Only a tiny fraction of the lightweight grains reaches a stigma