A dichotomous key is a key that gives you a way to classify an unknown plant by answering a series of questions.
Example of using the key: If I have a stone pine then I will go through these steps: has roots - go to 2, has tap roots - go to 4, doesn't have flowers - go to 6, non-strong taproot - which gives me stone pine.
| Question | Answer |
|---|---|
| 1a.Has roots | Go to 2 |
| 1b.Doesnt have roots | Go to 3 |
| 2a.Tap roots | Go to 4 |
| 2b.Non-tap roots | Go to 5 |
| 3a.Aquatic | Marsilea (Water clover) |
| 3b.Non-aquatic | Ophioglossum (Adder's tongue) |
| 4a.Flowers | Rosa (Roses) |
| 4b.No flowers | Go to 6 |
| 5a. Fibrous roots | Poaceae (Grasses) |
| 5b.Non-fibrous roots | Go to 7 |
| 6a. Strong taproot | Sempervirens (Evergreen) |
| 6b. Non-strong taproot | Pinus pinea (Stone pine) |
| 7a.Shallow roots | Go to 9 |
| 7b. Non-shallow roots | Go to 8 |
| 8a. Aerial roots | Ginkgo biloba (Ginkgo biloba) |
| 8b. Non-aerial roots | Go to 10 |
| 9a. Needles | Larix decidua (European larch) |
| 9b. Needle-like leaves | Picea pungens (Blue spruce) |
| 10a. Sporangia occur lower side of the leaves. | Solanum tuberosum (Potato ferns) |
| 10b. Needle-like leaves | Phymatosorus scolopendria (Monarch fern) |