Kingdom Plantae: the groups of plants

Five groups of plants

We sort plants with a few questions, asked in order.

1. Is the body divided into root, stem and leaf?
2. Does it have vascular tissue (xylem and phloem)?
3. Does it make seeds?
4. Are the seeds covered, in a fruit?

You should find that each "no" stops the key at once. With no vascular tissue you get a moss, whatever you choose for the seeds.

Thallophyta

The body is not divided into root, stem and leaf. These plants are the algae. They live mostly in water. Examples: Spirogyra, Ulothrix, Ulva and Chara.

Bryophyta

The body is flat or has a stem with small leaves. There is no vascular tissue. They live on land, but they need water to complete their life cycle. So they are called the amphibians of the plant kingdom. Examples: mosses and Marchantia.

Pteridophyta

The body is divided into root, stem and leaves, and it has vascular tissue. They have no seeds, and they reproduce by spores. On the underside of a fern leaflet are small brown dots, the sori, full of spores. Examples: ferns, Marsilea and horsetails.

Gymnosperms

The word means naked seed. The plants have seeds that are not covered by a fruit. They are mostly tall, woody, evergreen trees. Examples: pine, deodar and cycas.

Angiosperms

The word means covered seed. These are the flowering plants. The seeds are inside a fruit, and they are the biggest group of plants. The seed has a cotyledon, a seed leaf, that stores food. By the number of cotyledons, there are two kinds.

Try it in Python

This program is a key to the five groups of plants.

Practise with new numbers

Common mistakes

• Calling a fern a flowering plant. Ferns make no flowers and no seeds. They use spores.
• Thinking gymnosperms have no seeds. They have seeds, but the seeds are naked, not in a fruit.
• Mixing up monocots and dicots. Monocot: one cotyledon, parallel veins, fibrous roots.
• Thinking mosses carry water in xylem. Bryophytes have no vascular tissue at all.

Remember these

• Thallophyta: no root, stem or leaf. Bryophyta: no vascular tissue. Pteridophyta: vascular tissue, no seeds.
• Gymnosperms: naked seeds. Angiosperms: seeds in fruits.
• Angiosperms are monocots (one cotyledon) or dicots (two).
• Bryophytes are called the amphibians of the plant kingdom.

Check yourself

Try each one on your own first. If you are stuck, open a hint. Then check with Show the answer.

1. Which group has the ferns?

2. How many cotyledons does a bean seed have?

3. Why is a pine a gymnosperm?

4. The leaves of wheat have parallel veins. Is wheat a monocot or a dicot?