Question

In an urban garden, a student observes a plant where more than two leaves arise at each node, forming a circle. This phyllotaxy is seen in:

• A. Alstonia
• B. Hibiscus
• C. Calotropis
• D. Guava

Hint:

To easily remember leaf arrangements:
- Alternate: One leaf per node (e.g., Hibiscus)
- Opposite: Two leaves per node (e.g., Calotropis, Guava)
- Whorled: More than two leaves per node (e.g., Alstonia)

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question deals with plant morphology, specifically the arrangement of leaves on a stem, which is called phyllotaxy. We are asked to identify the plant that shows an arrangement where more than two leaves arise at each node and form a circle or whorl.

Step 2: Detailed Explanation:

• Phyllotaxy is the scientific term used to describe the pattern of leaf arrangement on a stem or branch. This arrangement is crucial because it ensures that leaves receive maximum sunlight with minimal overlapping.

• There are three main types of phyllotaxy: alternate, opposite, and whorled.

• Alternate phyllotaxy occurs when a single leaf arises at each node in an alternating fashion. Examples of this include Hibiscus (China rose), mustard, and sunflower.

• Opposite phyllotaxy occurs when a pair of leaves arises at each node and lies opposite to each other on the stem. This is observed in plants like Calotropis and Guava.

• Whorled (or verticillate) phyllotaxy is the arrangement where more than two leaves arise at a single node and form a circle or whorl around the stem. This specific arrangement is a characteristic feature of Alstonia and Nerium.

• Thus, the plant observed by the student with more than two leaves per node in a circle is Alstonia.

Step 3: Final Answer:
The whorled arrangement of leaves described in the observation is found in Alstonia.