Perigynium
Perigynium
Structure that encloses the ovary in Carex
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).[1][2] The perigynium is a modified prophyll, also known as a glume, which is tissue of leaf origin that encloses the dry, one-seeded achene.[3]
In liverworts, "perigynium" refers to a tube-shaped structure which encases the archegonium and the developing sporophyte.[4]
The location, size, shape, hairiness, color, and other aspects of the perigynium are important structures for distinguishing Carex species.[5] They are often subtended by a scale, which may also aid in identification.[5]