Look at these five leaves from Irish hedges, lawns and school gardens. How would you tell a friend which one is which — without pointing?

Here is one for something easy: the things in a pencil case. A pencil, a rubber, a ruler and a scissors.

Question 1: is it longer than your hand?
Yes: the ruler.
No: the pencil, the rubber and the scissors.

Question 2, for the no group: does it have a point?
Yes: the pencil and the scissors.
No: the rubber.

Every question splits the pile in two. Every path ends on a name. That is all a key is.

Soon you will build one for our leaves. That one is yours.

In groups, look closely at five leaves: oak, holly, dandelion, daisy and fern. Use a hand magnifier. What features can you see?

We will complete a yes-or-no branching key for our five leaves. Look at the branching key on the board.

The questions are:

• Does it have prickly edges?
• Is it divided into many small leaflets? (many small parts along a stem, like the fern)
• Does it have deep wavy lobes?
• Is the edge deeply jagged or toothed?

For each leaf, answer the questions in order. The first yes tells you its feature box: prickly edges, many small leaflets, deep wavy lobes, or a jagged or toothed edge. A leaf that gets no every time goes in smooth plain edge. When every leaf is in a box, we say which leaf is which: holly, fern, oak, dandelion or daisy.