Difference Between Alternate and Whorled Phyllotaxy

The key difference between alternate and whorled phyllotaxy is that in alternate phyllotaxy, there is a single leaf at each node of the plant stem while in whorled phyllotaxy, there are three or more leaves at each node of the plant stem.

Phyllotaxy is the arrangement of leaves on the stem of a plant. In fact, leaves are arranged on the stem in such a way that they can receive maximum sunlight in order to carry out photosynthesis. There are different types of phyllotaxies as alternate, opposite, whorled and spiral. Among them, alternate phyllotaxy is the commonest type of phyllotaxy; in this, only one leaf is present in each node. Whorled phyllotaxy is another type where three or more leaves are present at one node. However, in opposite phyllotaxy, two leaves arise from the stem at the same node, on opposite sides of the stem. Moreover, in spiral phyllotaxy, each leaf arises at a different point (node) on the stem, similar to alternate phyllotaxy. This article focuses on the difference between alternate and whorled phyllotaxy.

CONTENTS

1. Overview and Key Difference
2. What is Alternate Phyllotaxy
3. What is Whorled Phyllotaxy
4. Similarities Between Alternate and Whorled Phyllotaxy
5. Side by Side Comparison – Alternate vs Whorled Phyllotaxy in Tabular Form
6. Summary

What is Alternate Phyllotaxy?

Alternate phyllotaxy is the commonest type of leaf arrangement seen in plants. In an alternate leaf arrangement, there is only one leaf in one side of the node. The other side of the node does not have a leaf. In the next node, there is another leaf, but it arises from the side opposite to the origin of the previous leaf. Similarly, the leaves arise on the stem in an alternate pattern in two directions, especially in opposite directions. We can see alternate phyllotaxy in hibiscus, mustard, china rose and sunflower.

What is Whorled Phyllotaxy?

In a whorled phyllotaxy, three or more leaves arise from one node. Therefore, in each node, we can find more than three leaves at the same level.

This type of phyllotaxy is commonly seen in Alstonia plants. Moreover, nerium and spergula also show whorled leaf arrangement.

What are the Similarities Between Alternate and Whorled Phyllotaxy?

• Alternate and whorled are two major types of leaf arrangements on plant stems.
• Both phyllotaxies are commonly found in plants.

What is the Difference Between Alternate and Whorled Phyllotaxy?

Phyllotaxy is the pattern of leaf arrangement on the stem or branch of a plant. Alternate phyllotaxy is the comment type of leaf arrangement. In this type, only one leaf arises at each node. In contrast to this arrangement, in whorled phyllotaxy, three or more leaves arise at each node. So, this the key difference between alternate and whorled phyllotaxy.

Looking at some examples; mustard, china rose, hibiscus and sunflower plants show alternate phyllotaxy while alstonia, nerium, spergula plants show whorled phyllotaxy.

Below infographic summarizes the difference between alternate and whorled phyllotaxy.

Summary – Alternate vs Whorled Phyllotaxy

Mode of leaves arrangement on a plant stem is known as phyllotaxy. Alternate phyllotaxy and whorled phyllotaxy are two types. In alternate phyllotaxy, a single leaf arises at each node in an alternate manner. In whorled phyllotaxy, three or more than three leaves arise at each node. Thus, this is the key difference between alternate and whorled phyllotaxy.

Reference:

1. “Phyllotaxis.” Wikipedia, Wikimedia Foundation, 18 Oct. 2019, Available here.

Image Courtesy:

1. “Image from page 71 of “Class-book of botany [microform]: being outlines of the structures, physiology, and classification of plants : with a flora of the United States and Canada” (1881)” Internet Archive Book Images via Flickr
2. “Alstonia scholaris by kadavoor” By © 2009 Jee & Rani Nature Photography (CC BY-SA 4.0) via Commons Wikimedia