ˌ ̷ ̷ ̷ ̷ˈkēd.ēəm noun
( plural perichae·tia -d.ēə)
Etymology: New Latin, from peri- + Greek chaitē flowing hair, mane, foliage + New Latin -ium — more at chaeta
: an enveloping sheath in a bryophyte ; especially : a cluster of modified leaves surrounding the sex organs or later the seta of mosses