Calyptra vs. Perigynium — What's the Difference?
By Fiza Rafique & Maham Liaqat — Updated on March 24, 2024
Calyptra is a protective cap in mosses and some liverworts, while perigynium envelops the ovary in some flowering plants.
Difference Between Calyptra and Perigynium
Table of Contents
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Key Differences
Calyptra originates from the gametophyte generation in mosses and liverworts, serving as a protective covering for the developing sporophyte, especially the capsule containing spores. It is formed from the tissue of the female gametophyte, detaching as the sporophyte matures. On the other hand, the perigynium is a structure found in some flowering plants, notably in the sedge family (Cyperaceae), where it surrounds and sometimes encloses the ovary or base of the flower. This feature is critical for identification and classification within the family.
While the calyptra's primary role is to protect the developing sporophyte, especially in its early stages, and to ensure a successful transition from gametophyte to sporophyte generation, the perigynium's function varies among species but often involves aiding in the dispersal of seeds or fruits. Its presence can influence the plant's reproductive strategies and can be an adaptation to specific environmental conditions.
The calyptra is usually a temporary structure, sloughing off or decaying once the sporophyte matures and is ready to release spores. This reflects its role in early developmental stages. In contrast, the perigynium may persist around the fruit or seed, even after fertilization and maturation, contributing to seed dispersal mechanisms such as wind or animal dispersal in some species.
Morphologically, the calyptra can vary in shape and size among different moss and liverwort species but is generally cap-like and envelops the upper part of the developing sporophyte. The perigynium, however, can exhibit a wide range of forms, from sack-like structures that fully enclose the ovary to bristle-like formations, depending on the species and its specific ecological adaptations.
The presence and characteristics of the calyptra are key diagnostic features in the identification and study of mosses and liverworts, contributing to our understanding of their life cycles and evolutionary relationships. Similarly, the perigynium is a crucial feature for identifying species within the sedge family, offering insights into the evolutionary adaptations and ecological niches occupied by these plants.
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Comparison Chart
Definition
Cap-like structure covering the developing sporophyte in mosses and liverworts.
Structure surrounding or enclosing the ovary in some flowering plants, particularly in the sedge family.
Origin
Derived from the gametophyte's tissue.
Forms from the surrounding bracts or floral parts.
Function
Protects the young sporophyte and aids in moisture retention during early development.
Often aids in seed or fruit dispersal; its form can be adaptive to environmental conditions.
Persistence
Temporary, detaches as the sporophyte matures.
May persist around the fruit or seed, aiding in dispersal.
Morphological Variability
Generally cap-like, varying among species.
Ranges from sack-like to bristle-like, highly variable among species.
Compare with Definitions
Calyptra
A protective cap that covers the sporophyte in mosses.
The calyptra fell off as the moss matured.
Perigynium
Envelopes the ovary in certain flowering plants.
The perigynium's presence is characteristic of many sedges.
Calyptra
Derived from the female gametophyte in liverworts.
The liverwort's calyptra is essential for sporophyte development.
Perigynium
Persists around the fruit or seed in some species.
The retained perigynium facilitates seed distribution by animals.
Calyptra
Temporary and detaches upon sporophyte maturity.
The calyptra's detachment signifies the moss sporophyte's readiness to disperse spores.
Perigynium
Important for species identification in the sedge family.
Sedge identification often relies on perigynium characteristics.
Calyptra
Varies in shape among species.
The calyptra's shape can help identify the moss species.
Perigynium
Contributes to seed dispersal mechanisms.
The perigynium can aid in wind dispersal of seeds.
Calyptra
Plays a key role in the moss life cycle.
The calyptra protects the developing sporophyte from environmental stress.
Perigynium
Highly variable in form among species.
The perigynium's form varies widely, reflecting ecological adaptations.
Calyptra
The protective cap or hood covering the spore case of a moss or related plant.
Perigynium
In botany, a perigynium (plural: perigynia), also referred to as a utricle, typically refers to a sac that surrounds the achene of plants in the genus Carex (Cyperaceae). The perigynium is a modified prophyll, tissue of leaf origin, that encloses the dry, one-seeded achene.In liverworts, "perigynium" refers to a tube-shaped structure which encases the archegonium and the developing sporophyte.The location, size, shape, hairiness, color, and other aspects of the perigynium are important structures for distinguishing Carex species.
Calyptra
A similar hoodlike or caplike structure, such as a root cap.
Perigynium
(botany) Any unusual appendage around the pistil, such as the bottle-shaped body in the sedges, or the bristles and scales in some other genera of the sedge family.
Calyptra
(botany) In bryophytes, a thin, hood of tissue that forms from the archegonium and covers the developing sporophyte and is shed as it ripens.
Perigynium
Some unusual appendage about the pistil, as the bottle-shaped body in the sedges, and the bristles or scales in some other genera of the Sedge family, or Cyperaceæ.
Calyptra
(botany) any cap-like covering of a flower or fruit, such as the operculum over the unopened buds of Eucalyptus flowers
Calyptra
(botany) Any of various coverings at the tips of structures, in the terminology of various authors; for example rootcaps and the apical cells of trichomes.
Calyptra
(entomology) In flies such as the housefly, Musca, in the taxonomic order Diptera, zoological section Schizophora, subsection Calyptrata, the calyptra is a membranous rearward extension of the forewing; it covers the haltere.
Calyptra
A little hood or veil, resembling an extinguisher in form and position, covering each of the small flasklike capsules which contain the spores of mosses; also, any similar covering body.
Calyptra
The hood or cap covering the calyx of certain plants: e.g., the California poppy
Common Curiosities
What is a perigynium?
A structure that surrounds or encloses the ovary in certain flowering plants, particularly in the sedge family.
What is a calyptra?
A cap-like structure that covers and protects the developing sporophyte in mosses and liverworts.
Are calyptra and perigynium the same?
No, they are distinct structures found in different groups of plants and serve different functions.
Is the perigynium important for identifying sedge species?
Yes, its characteristics are crucial for species identification within the sedge family.
How does the calyptra function in mosses?
It protects the young sporophyte and aids in moisture retention during its early development stages.
What role does the perigynium play in plants?
It often aids in seed or fruit dispersal and can be adapted to specific environmental conditions.
Can the perigynium influence seed dispersal?
Yes, its presence and form can contribute to various seed dispersal mechanisms.
Does the calyptra remain on the moss throughout its life?
No, it is temporary and detaches once the sporophyte matures.
Do all mosses have a calyptra?
Most mosses develop a calyptra as part of their reproductive cycle, but its prominence can vary.
How does the perigynium's form relate to its function?
Its form can vary to support different dispersal strategies, such as wind or animal dispersal.
How can the calyptra help in identifying moss species?
Its shape and presence can provide clues to the species' identity and developmental stage.
Do all sedges have a perigynium?
Many, but not all, sedge species have a perigynium, which is a key feature for identification.
What happens to the calyptra after it detaches from the moss?
It usually decays or disintegrates, having served its protective role.
Can the presence of a calyptra indicate the health of a moss?
The presence and condition of a calyptra can indicate the developmental stage and potentially the health of a moss.
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Written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
Co-written by
Maham Liaqat
