INDUSIUM

indusium

(noun) a membrane enclosing and protecting the developing spores especially that covering the sori of a fern

Source: WordNet® 3.1

Etymology

Noun

indusium (plural indusia)

(botany) A protecting membrane, especially that covering the developing spores of a fern.

Source: Wiktionary

In*du"si*um, n.; pl. Indu. Etym: [L., an under garment, fr. induere to put on: cf. F. indusie the covering of the seed spots of ferns.] (Bot.) (a) A collection of hairs united so as to form a sort of cup, and inclosing the stigma of a flower. (b) The immediate covering of the fruit dots or sori in many ferns, usually a very thin scale attached by the middle or side to a veinlet. (c) A peculiar covering found in certain fungi.

Source: Webster’s Unabridged Dictionary 1913 Edition