Dichotomous key tree worksheet Interactive Worksheet - Edform - Free Printable

Let's solve this dichotomous key practice problem step by step.

We are given 5 leaves (A, B, C, D, E) and a dichotomous key to identify them. We'll use the key to determine which tree each leaf comes from.

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🔍 Step-by-step analysis using the dichotomous key:

#### Step 1: Determine if the leaf is oval or star-shaped

- Oval-shaped → go to Step 2
- Star-shaped → go to Step 3

Let’s examine each leaf:

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✔ Leaf A:

- Shape: Oval, with smooth edges
- So: Go to Step 2

#### Step 2:
- 2A: Leaf is shorter wide → Go to Step 4
- 2B: Leaf is longer and narrow → Hickory

Leaf A is shorter and wider, so go to Step 4

#### Step 4:
- 4A: Leaf has 4 veins on each side → Birch
- 4B: Leaf has 5 veins on each side → Beech

Leaf A has about 4 veins per side → Birch

✔ A = Birch

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✔ Leaf B:

- Shape: Oval, with jagged edges
- So: Go to Step 2

#### Step 2:
- It's shorter and wide → go to Step 4

#### Step 4:
- Count veins: looks like 4 veins on each side → Birch

Wait! But Leaf B has jagged edges — but we’re not checking that yet.

But wait: Step 4 only applies after Step 2, and it’s based on vein count.

But here's a problem: Birch is listed under Step 4A, but only if the leaf has smooth edges? No — actually, the key doesn't mention edge type in Step 4.

Wait — let’s double-check the flow.

Actually, Step 2 only splits on width/length, not edges.

So for Leaf B: oval → Step 2 → shorter and wide → Step 4

Now, Step 4:
- 4A: 4 veins per side → Birch
- 4B: 5 veins per side → Beech

Leaf B has 5 veins per side → Beech

✔ B = Beech

Wait — but earlier I thought it had jagged edges. That might be a clue.

But the key does not ask about edge type until Step 3, which is only for star-shaped leaves.

So Leaf B is oval, so Step 3 does not apply.

So we don’t care about jagged edges for oval leaves — they're handled in Step 2 → Step 4.

So yes, B = Beech

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✔ Leaf C:

- Shape: Star-shaped (lobed, like a maple)
- So: Go to Step 3

#### Step 3:
- 3A: Leaf has smooth edges → Sweetgum
- 3B: Leaf has jagged edges → Sugar Maple

Leaf C has jagged edges → Sugar Maple

✔ C = Sugar Maple

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✔ Leaf D:

- Shape: Oval, with smooth edges
- So: Go to Step 2

#### Step 2:
- 2A: Leaf is shorter and wide → Step 4
- 2B: Longer and narrow → Hickory

Leaf D is longer and narrow → Hickory

✔ D = Hickory

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✔ Leaf E:

- Shape: Star-shaped, with jagged edges
- So: Go to Step 3

#### Step 3:
- 3A: Smooth edges → Sweetgum
- 3B: Jagged edges → Sugar Maple

Leaf E has jagged edges → Sugar Maple

Wait — but Leaf C is also Sugar Maple?

Yes, both C and E have star-shaped, jagged-edged leaves.

But let’s look closely:

- Leaf C: more lobed, like a typical sugar maple
- Leaf E: also lobed, but maybe more pointed?

Wait — but both C and E appear to be star-shaped with jagged edges → both should be Sugar Maple?

But the question asks us to identify each of the five leaves, so possibly two are Sugar Maple?

Let’s check the key again.

The key says:

- 3B: Leaf has jagged edges → Sugar Maple

It doesn't differentiate further.

So any star-shaped leaf with jagged edges is Sugar Maple.

But wait — Leaf C and E both look like maple leaves.

But let’s compare:

- Leaf C: has 5 lobes, deep sinuses — classic sugar maple
- Leaf E: also 5 lobes, but more pointed — also sugar maple

So both could be Sugar Maple

But let’s check Leaf A, B, D:

We have:
- A: Birch
- B: Beech
- C: Sugar Maple
- D: Hickory
- E: Sugar Maple

But wait — Leaf E has more pronounced lobes, but still fits "star-shaped".

But is there a mistake?

Wait — Leaf D is long and narrow → Hickory → correct.

Leaf A: oval, short and wide, 4 veins → Birch

Leaf B: oval, short and wide, 5 veins → Beech

Leaf C: star-shaped, jagged → Sugar Maple

Leaf E: star-shaped, jagged → Sugar Maple

So two Sugar Maples?

But let’s double-check Leaf E — is it really star-shaped?

Yes — it has multiple points, like a maple.

But wait — is there another possibility?

No — the key only gives one option for star-shaped + jagged edges: Sugar Maple

So unless there’s a typo, C and E are both Sugar Maple

But perhaps the image shows different types?

Wait — let’s re-express the key clearly.

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Let's list the key again:

| Step | Choice | Outcome |
|------|--------|---------|
| 1A | Oval | → Step 2 |
| 1B | Star-shaped | → Step 3 |
| 2A | Shorter and wide | → Step 4 |
| 2B | Longer and narrow | → Hickory |
| 3A | Smooth edges | → Sweetgum |
| 3B | Jagged edges | → Sugar Maple |
| 4A | 4 veins per side | → Birch |
| 4B | 5 veins per side | → Beech |

So now, let’s analyze each leaf visually:

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🌿 Leaf A:

- Shape: Oval
- Edges: Smooth
- Size: Short and wide
- Veins: ~4 per side

→ Step 1A → Step 2A → Step 4A → Birch

✔ A = Birch

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🌿 Leaf B:

- Shape: Oval
- Edges: Jagged (toothed)
- Size: Short and wide
- Veins: ~5 per side

→ Step 1A → Step 2A → Step 4B → Beech

✔ B = Beech

Note: The jagged edges don't matter here because only star-shaped leaves go to Step 3. Oval leaves skip that.

So even though it has jagged edges, since it's oval, we follow the oval path.

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🌿 Leaf C:

- Shape: Star-shaped (lobed)
- Edges: Jagged
- → Step 1B → Step 3B → Sugar Maple

✔ C = Sugar Maple

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🌿 Leaf D:

- Shape: Oval
- Edges: Smooth
- Size: Long and narrow
- → Step 1A → Step 2B → Hickory

✔ D = Hickory

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🌿 Leaf E:

- Shape: Star-shaped
- Edges: Jagged
- → Step 1B → Step 3B → Sugar Maple

✔ E = Sugar Maple

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Final Answers:

| Leaf | Tree Name |
|------|------------------|
| A | Birch |
| B | Beech |
| C | Sugar Maple |
| D | Hickory |
| E | Sugar Maple |

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✔ Answer Sheet:

```
A) Birch
B) Beech
C) Sugar Maple
D) Hickory
E) Sugar Maple
```

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💡 Explanation Summary:

- Use the dichotomous key by making choices at each step.
- Start with shape: oval or star-shaped
- For oval: then check length (wide vs. narrow), then vein count
- For star-shaped: check edge type (smooth vs. jagged)
- Jagged edges in star-shaped → Sugar Maple
- Smooth edges in star-shaped → Sweetgum
- Long and narrow oval → Hickory
- Short and wide oval → check veins: 4 → Birch, 5 → Beech

Even though Leaf E has jagged edges, it's star-shaped, so it goes to Step 3, and jagged → Sugar Maple

So both C and E are Sugar Maple

This is possible — multiple leaves can be the same species.

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✔ Final Answer:

- A: Birch
- B: Beech
- C: Sugar Maple
- D: Hickory
- E: Sugar Maple