In which of the following plant small specialised roots called coralloid roots are associated with N2-fixing cyanobacteria.

Options

A. Leguminous plant
B. Cycas
C. Pinus
D. Ginkgo

Answer

To determine which plant has small specialized roots called coralloid roots that are associated with nitrogen-fixing cyanobacteria, we can analyze the options provided:

1. **Lagumanias plant**: This plant is not known for having coralloid roots associated with nitrogen-fixing cyanobacteria.

2. **Cycle**: This option seems to be a typographical error. It might refer to "Cycad," which is a group of plants that includes the Cycus.

3. **Pinus**: Pinus (pine trees) do not have coralloid roots associated with nitrogen-fixing cyanobacteria.

4. **Ginkgo**: Ginkgo trees are also not associated with coralloid roots or nitrogen-fixing cyanobacteria.

Now, focusing on the correct plant:

- **Cycus**: The Cycus plant, which belongs to the Cycad family, is known for having specialized roots called coralloid roots. These roots are symbiotically associated with nitrogen-fixing cyanobacteria, which help the plant in nitrogen fixation.

Thus, the correct answer is **Cycus**.

### Step-by-Step Solution:
1. **Identify the plants listed in the options**: Lagumanias, Cycle, Pinus, Ginkgo.
2. **Understand the concept of coralloid roots**: These are specialized roots that have a symbiotic relationship with nitrogen-fixing cyanobacteria.
3. **Evaluate each option**:
- Lagumanias: Not associated with coralloid roots.
- Cycle: Likely refers to Cycad (Cycus).
- Pinus: Not associated with coralloid roots.
- Ginkgo: Not associated with coralloid roots.
4. **Conclude**: The Cycus plant has coralloid roots associated with nitrogen-fixing cyanobacteria.