Definition of: indusium

(in·d′zē·əm, -zhē-, -dy′-) noun plural ·si·a (-zē·ə, -zhē·ə)
1. Bot. a An outgrowth of a fern leaf covering the immature sori or fruit clusters, b A hairy cup surrounding the stigma in a flower.
2. Biol. a The larval case of an insect, b Any similar membranous envelope, as the amnion. [<L, a tunic <induere put on; infl. in form by Gk. endysis dress, garment <endyein put on]
—in·du′si·al adjective