Dichotomous Key Practice Worksheet: Identify the 5 Leaves Using a Step-by-Step Key

Let’s go step by step to identify each leaf using the dichotomous key.

We have 5 leaves: A, B, C, D, E.

The key starts at STEP 1:

STEP 1:
- 1A: Leaf is oval shaped → Go to step 2
- 1B: Leaf is star shaped → Go to step 3

Look at each leaf:

Leaf A: Looks like a typical oak or maple? Wait — let’s check shape. It has lobes but not really “star” shaped. Actually, looking closely, it’s more oval with some curves — but wait, let’s compare to others.

Actually, let’s look at Leaf C and E — they are clearly star-shaped (like maple leaves). So those will go to Step 3.

Leaf A: Has a broad base and tapers to a point — could be considered oval? Let’s hold that thought.

Leaf B: Very clearly oval — smooth outline, no deep lobes. Definitely oval.

Leaf D: Long and narrow — also looks oval-ish, but maybe longer? We’ll see.

Leaf C: Star-shaped (maple-like) → goes to Step 3

Leaf E: Also star-shaped (oak-like?) → goes to Step 3

So for now:

Leaves going to Step 2 (oval): A, B, D
Leaves going to Step 3 (star): C, E

Wait — let’s double-check Leaf A. Is it oval? Compared to B and D, it has more irregular edges. But in botany, “oval” can include slightly lobed leaves if the overall shape is elliptical. However, looking at the key, Step 1 says “oval shaped” vs “star shaped”. Star shaped means multiple pointed lobes radiating out — like C and E.

Leaf A has one main lobe on top and sides curved — actually, it might still be considered oval. Let’s proceed and verify later.

But let’s look at the options in Step 2:

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

So if a leaf is long and narrow, it’s Hickory.

Which of A, B, D is long and narrow?

Leaf D is very long and narrow — so D should be Hickory.

Then A and B are shorter and wider → go to Step 4.

Now Step 4:

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

Look at Leaf A: Count the veins. From the drawing, it seems to have about 5 major veins branching from the center on each side? Let’s count carefully.

In Leaf A: The central vein, then on left side: 1,2,3,4,5? Actually, looking at the diagram, Leaf A has 5 distinct veins on each side (including the ones near the tip). Similarly, Leaf B: looks like it has 4 veins on each side.

Confirm:

Leaf A: Veins — starting from bottom, you can see 5 clear branches on each side → so 5 veins → Beech

Leaf B: Only 4 visible veins on each side → Birch

So:

D = Hickory (from Step 2B)

A = Beech (Step 4B)

B = Birch (Step 4A)

Now back to C and E — they went to Step 3.

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

Look at Leaf C: Edges are smooth? No — actually, Leaf C has rounded lobes but the edge between lobes is smooth? Wait — in the drawing, Leaf C has smooth margins (no teeth), while Leaf E has sharp, jagged edges.

Leaf C: Smooth edges → Sweetgum

Leaf E: Jagged edges → Sugar Maple

Wait — let’s confirm:

Leaf C: Maple-like but with smooth sinuses (the indentations between lobes) — yes, often called “smooth-edged maple” but according to key, 3A is Sweetgum.

Sweetgum leaves are star-shaped with smooth edges — yes.

Sugar Maple has jagged/toothed edges — yes, Leaf E shows that.

So:

C = Sweetgum

E = Sugar Maple

Now let’s list all:

A: Beech

B: Birch

C: Sweetgum

D: Hickory

E: Sugar Maple

Double-check against the key:

Start with A:

A → Step 1: Oval? Yes → Step 2

Step 2: Shorter wide? Yes → Step 4

Step 4: 5 veins? Yes → Beech ✔️

B → Step 1: Oval → Step 2

Step 2: Shorter wide → Step 4

Step 4: 4 veins → Birch ✔️

C → Step 1: Star shaped → Step 3

Step 3: Smooth edges → Sweetgum ✔️

D → Step 1: Oval → Step 2

Step 2: Longer and narrow → Hickory ✔️

E → Step 1: Star shaped → Step 3

Step 3: Jagged edges → Sugar Maple ✔️

Perfect.

Final Answer:
A) Beech
B) Birch
C) Sweetgum
D) Hickory
E) Sugar Maple