Difference between hypogynous and epigynous flower is mainly due to the following factors, namely the position of an ovary and attachment of perianth and androecium.
Position of the ovary: An ovary is a flower’s female reproductive structure that constitutes Gynoecium along with stigma and style. A hypogynous flower consists of a superior ovary, whereas epigynous flower consists of an inferior ovary.
Attachment of perianth: The combination of calyx and corolla makes up the outer whorl that collectively refers as “Perianth”. In hypogynous flower, the sepals and petals freely adhere to the thalamus below the ovary, whereas in epigynous flower the sepals and petals adhere to the thalamus above the ovary.
Attachment of androecium: It represents the male reproductive part that comprises stamens having a long, slender filament and anther carrying pollen grains. The flowers showing hypogyny consist of stamens that can remain free at the base of an ovary. In contrast, the flowers showing epigyny consists of stamens that remain fused on the tip of the thalamus, above the ovary.
Content: Hypogynous Vs Epigynous Flower
Comparison Chart
| Properties | Hypogynous Flower | Epigynous Flower |
|---|---|---|
| Meaning | It can define as the flower, where all the floral whorls are found under the ovary | It can define as the flower, where all the floral whorls are found on the top of the ovary |
| Position of an ovary | It consists of free and superior ovary | It consists of adherent and inferior ovary |
| Androperianth attachment | The androperianth whorl is fixed to the thalamus below the ovary | The androperianth whorl is fixed to the thalamus above the ovary |
| Receptacle shape | It consists of convex or conical shaped thalamus | It consists of flask-shaped thalamus |
| Receptacle expansion | Receptacle is non-expanded, except for the central projection | Receptacle is expanded or hollowed out to enclose an ovary |
| Thalamus attachment | The receptacle is freely attached to the wall of ovary | The receptacle is fused with the wall of ovary |
| Calyx | It comprises free and inferior calyx | It comprises adherent and superior calyx |
| Corolla | These are inserted on the receptacle | These are inserted above the ovary |
| Pistil | In this type, the whole pistil is visible | In this type, only stigma and style are visible |
| Examples | Beans, peas, tomatoes, drupes etc. | Banana, squash, melon, apple, daffodil etc. |
Definition
Hypogynous flower: We can understand the term hypogynous, by breaking the terms into two like hypo and gynous. Hypo means under, and gynous means gynoecium or ovary. Thus, we can define that in a hypogynous flower, the floral whorls attach to the thalamus under the ovary. Therefore, it comprises of a superior ovary and inferior floral parts like sepals, petals and stamens. In this flower, the attachment of androperianth and receptacle is free, i.e. these are not fused with the wall of the ovary.
Epigynous flower: We can understand the term epigynous, by breaking the term into two like epi and gynous. Epi means above, and gynous means gynoecium or ovary. Thus, we can define that in an epigynous flower, the floral whorls attach to the thalamus above the ovary. Therefore, it comprises an inferior ovary and superior floral parts like sepals, petals and stamens. In epigynous flower, the attachment of androperianth and receptacle is fused,i.e. these are not freely attached to the wall of the ovary.
Key Differences Between Hypogynous and Epigynous Flower
- Hypogynous flower comprises a superior ovary, where all the floral whorls originate from the thalamus, under the gynoecium. The epigynous flower contains an inferior ovary, where all the floral whorls originate upwards the thalamus, above the gynoecium.
- The receptacle or torus appears conical-shaped that freely attaches to the wall of the ovary in a hypogynous flower. The epigynous flower consists thalamus of flask-shaped that encloses the ovary.
- The components of androperianth develop independently from the conical thalamus in hypogynous flower. Oppositely, the components of androperianth grow conjointly from the tip of hollowed-out thalamus in epigynous flower.
- The sepals, petals and stamens are inferior in position with respect to the location of an ovary in a flower showing hypogyny. In contrast, the androperianth in epigynous flower is superior to the ovary.
- The pistil comprising stigma, style and ovary are clearly visible in hypogynous flower. In epigynous flower, only stigma and style are apparently visible.
Conclusion
Despite many differences, both hypogynous and epigynous flowers can classify depending on the position of the floral whorls like perianth and androecium with respect to the position of the ovary. Therefore, the basis for the flower characterization can also determine by the location and attachment of floral whorls and accessory components.