Question

Given below are the number of leaves of successive nodes in different orthostiches in a plant having alternate phyllotaxy. What is the angle of leaf divergence ?

• A. ${180}^0$
• B. ${120}^0$
• C. ${135}^0$
• D. ${160}^0$

Answer 1

The correct option is B ${120}^0$

B. 120°

Reason: In the common sedge (Cyperus rotundus) the leaves are three-ranked (three orthostichies); the fourth leaf is above the first leaf, fifth above second, sixth above third and so on. Three leaves lie in one circle of the genetic spiral. Hence, angular divergence = 1/3 of 360° = 120° or 1/3 phyllotaxy.