Question

Amongst pea tendrils, opuntia spines, lemon thorns and cucurbit tendrils.

Which ones are homologous structures?

Why do you call them homologous?

Answer 1

• Pea tendrils and opuntia spines are homologous.
• Lemon thorm and cucurbit tendrils are homologous.

Reason:

• Pea tendrils and Opuntia spines are modified leaves (same orign) but perform different functions.
• Lemon thorns and cucurbit tendrils are modified stems. Both arise from axillary position. Both perform different functions.