Model Answer
0 min readIntroduction
The cyathium is a highly specialized inflorescence characteristic of the genus *Euphorbia* (family Euphorbiaceae). It represents a significant evolutionary adaptation, often mistaken for a single flower due to its compact structure. The cyathium is a pseudanthium – a structure that appears to be a single flower but is actually a cluster of reduced flowers surrounded by modified bracts. Understanding its anatomy is crucial for comprehending the reproductive strategies and phylogenetic relationships within the Euphorbiaceae family. This detailed description will focus on the T.S. of a typical *Euphorbia* cyathium, highlighting its key features.
T.S. of Cyathium of *Euphorbia*
The transverse section of a *Euphorbia* cyathium reveals a complex arrangement of structures. The following points detail the key features observed in a typical T.S.:
1. Involucre
The outermost layer is formed by the involucre, which is a whorl of bracts (involucral bracts). These bracts are often green and leaf-like, providing protection to the developing floral structures. They are arranged in multiple rows and may be slightly fused at their bases.
2. Cyathophylls
Inside the involucre are cyathophylls, which are modified leaves that surround the flowers. These are typically brightly colored (often yellow or red) and serve to attract pollinators. They are arranged in a spiral or whorled pattern.
3. Glands (Nectaries)
A prominent feature of the cyathium is the presence of numerous glands, often located at the base of the cyathophylls. These glands secrete nectar, attracting insects for pollination. They appear as circular or oval structures in the T.S.
4. Male Flowers
The male flowers are highly reduced, typically consisting of a single stamen (filament and anther). They are numerous and arranged around the central female flower. The anthers are often small and dehisce explosively, releasing pollen.
5. Female Flower
The female flower is also reduced, consisting of a single pistil (stigma, style, and ovary). The ovary is usually superior and contains one or more ovules. The stigma is often branched or lobed to increase the surface area for pollen reception.
6. Peduncle
The cyathium is borne on a peduncle, which is a stalk that connects the inflorescence to the main stem. The vascular bundles are visible within the peduncle.
Here's a tabular representation summarizing the key components:
| Component | Description | Function |
|---|---|---|
| Involucre | Whorl of bracts | Protection of floral parts |
| Cyathophylls | Modified leaves | Attract pollinators |
| Glands | Nectar-secreting structures | Attract pollinators |
| Male Flower | Single stamen | Pollen production |
| Female Flower | Single pistil | Ovule protection and fertilization |
7. Vascular Bundles
The cyathium exhibits a complex vascular arrangement. Vascular bundles are present in the peduncle, involucre, and cyathophylls, providing nourishment and support to the developing floral structures. The arrangement of vascular bundles can be used to identify the different parts of the cyathium.
Pollination Mechanism: The cyathium relies on insect pollination, primarily by small beetles and flies. The nectar glands attract these insects, which inadvertently transfer pollen from the male flowers to the stigma of the female flower. The explosive pollen release mechanism further aids in pollination.
Conclusion
The T.S. of the *Euphorbia* cyathium reveals a remarkable adaptation for reproduction. Its unique structure, characterized by reduced floral parts and specialized bracts and glands, demonstrates the evolutionary pressures that have shaped plant morphology. Understanding the anatomy of the cyathium is essential for appreciating the diversity and complexity of plant reproductive strategies. Further research into the genetic mechanisms controlling cyathium development could provide valuable insights into plant evolution and breeding.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.