perigynium

in sedges

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July 23, 2026

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The term "perigynium" has two primary meanings. In bryophytes, it refers to a fleshy cup or tube surrounding the archegonium, formed from the stem or thallus.1

In sedges, specifically within the genus Carex, the perigynium is a saclike bract that encloses the achene (seed). This structure can vary in form, from tightly enveloping the achene to being inflated, flattened, or even fleshy. Some species of Carex have food bodies at the base of the perigynium to aid in dispersal by ants. The perigynium is a unique characteristic of this genus within the sedge family (Cyperaceae).21

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Cyperaceae
Characteristic morphological features
…in a sac called a perigynium, a modified tubular bract. The perigynium may tightly envelop the achene or it may be inflated like a bladder, flattened and scalelike, or even fleshy and edible. Many woodland species of Carex have food bodies (elaiosomes) at the base of the perigynium for ants,…
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…in a sac called a perigynium, a modified tubular bract. The perigynium may tightly envelop the achene or it may be inflated like a bladder, flattened and scalelike, or even fleshy and edible. Many woodland species of Carex have food bodies (elaiosomes) at the base of the perigynium for ants,…
Read More