The large, thin-walled cells found in the upper epidermis of a monocot leaf are known as:

1. The monocot leaf has stomata on both upper and lower epidermis. 2. Some upper epidermal cells are unusually large and thin-walled. 3. These special cells are the bulliform cells. 4. So bulliform cells is the correct answer. 5. Option B guard cells flank the stomata and are small, the trap. 6. Option A bundle sheath cells surround a vascular bundle, so they are wrong. 7. Option D companion cells lie in the phloem, not the epidermis. _Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 12 Plant Anatomy and Plant Physiology "Internal Structure of Monocot Leaf", p.186_