A foliar parasite is

Options

A. Dendrophthoe
B. Cistanche
C. Ileostylus
D. Gaiadendron.

Answer

### Step-by-Step Solution:

1. **Understanding Foliar Parasites**:
- A foliar parasite is a type of plant that grows on another plant (the host) but does not have roots that penetrate the soil. Instead, it relies on its host for nutrients and water.

2. **Characteristics of Foliar Parasites**:
- They are rootless and grow on the leaves or stems of other plants.
- They use a specialized structure called a haustorium to penetrate the host plant and extract nutrients.

3. **Identifying Options**:
- We need to evaluate the given options to identify which one is a foliar parasite.
- The options provided are:
- Dendrophteoides
- Sistentiae
- Eleostylus
- Gydandron

4. **Analyzing Each Option**:
- **Dendrophteoides**: This is a hemiparasite, meaning it can photosynthesize but also relies on a host for some nutrients. This option is incorrect.
- **Sistentiae**: This is a holoparasite, which means it cannot photosynthesize and is entirely dependent on its host. This option is also incorrect.
- **Eleostylus**: This is identified as mistletoe, which is a classic example of a foliar parasite. This option is correct.
- **Gydandron**: This is a parasitic shrub or tree, which does not fit the definition of a foliar parasite. This option is incorrect.

5. **Conclusion**:
- The correct answer is **Eleostylus**, which is a foliar parasite (mistletoe).