perigynium

noun

(Gr. peri: around; gynę: female) (pl. perigynia). 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 Cyperaceć; in bryophytes, a somewhat fleshy, tubular structure around the archegonial cluster and subsequent sporophyte, derived from axial cells peripheral to the archegonial cluster, a perigynium may or may not be associated with a shoot calyptra, e.g. the hollow perigynium of Isotachis.