Question

Which of the following are the examples of monocot broadleaved weeds?
(A) Commelina benghalensis
(B) Eichhornia crassipes
(C) Amaranthus viridis
(D) Plantago lanceolata

• A. (A), (B), (C) and (D)
• B. (A) and (B) only
• C. (B) and (C) only
• D. (C) and (D) only

Hint:

While most agricultural monocots are narrow-leaved (like grasses and sedges), weeds in the families Commelinaceae (Dayflowers) and Pontederiaceae (Water Hyacinths) are key exceptions that have broad leaves.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Weeds are classified based on their botanical class (monocotyledons vs. dicotyledons) and their leaf morphology (narrow-leaved vs. broad-leaved).
While most monocot weeds are narrow-leaved grasses, certain monocotyledonous families produce broad leaves.

Step 3: Detailed Explanation:
Let us evaluate each weed listed:
- Commelina benghalensis (A): Belonging to the family Commelinaceae, this plant is a monocotyledon but possesses broad, ovate leaves. It is classified as a monocot broad-leaved weed.
- Eichhornia crassipes (B): Belonging to the family Pontederiaceae, this aquatic weed is a monocotyledon that produces broad, bulbous leaves. It is classified as a monocot broad-leaved weed.
- Amaranthus viridis (C): This is a dicotyledonous weed belonging to the family Amaranthaceae, classified as a dicot broad-leaved weed.
- Plantago lanceolata (D): This is a dicotyledonous weed belonging to the family Plantaginaceae, classified as a dicot broad-leaved weed.
Therefore, only (A) and (B) represent monocot broad-leaved weeds.

Step 4: Final Answer:
The monocot broad-leaved weeds are Commelina benghalensis and Eichhornia crassipes.