Question

Which of the following is partial stem parasite :

• A. Cassytha filiformis
• B. Viscum spp.
• C. Cuscuta reflexa
• D. Asplenium spp.

Hint:

Remember: Total parasites are yellow or orange (lacking chlorophyll, like Cuscuta), while Partial parasites are green (possessing chlorophyll but lacking roots, like Viscum).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Parasitic plants depend on host plants for some or all of their nutritional and water requirements.
They are classified as either stem or root parasites, and further sub-classified as total (holoparasites) or partial (hemiparasites).

Step 2: Detailed Explanation:
Let us evaluate each of the options provided:
1. Partial stem parasites (Hemiparasites) possess green leaves containing chlorophyll and can perform photosynthesis to produce their own organic food.
However, they lack a true root system and must tap into the host tree's xylem using specialized sucking structures called haustoria to obtain water and essential mineral nutrients.
Viscum species (mistletoes) are classic examples of partial stem parasites that grow on the branches of various forest trees.
2. Total stem parasites (Holoparasites) lack chlorophyll and leaves, meaning they cannot photosynthesize.
They rely entirely on the host plant's vascular system (both xylem and phloem) for water, minerals, and organic food.
Cuscuta reflexa (Amarbel) and Cassytha filiformis are total stem parasites.
3. Asplenium species are epiphytic or terrestrial ferns that grow on trees for physical support, but they are not parasitic.

Step 3: Final Answer:
Therefore, the partial stem parasite among the options is Viscum spp., corresponding to option (B).