leptosporangium

Noun

 * 1)  A sporangium formed from a single epidermal cell.
 * 2) * 2003, Jill Bailey, Filicinophyta (ferns), entry in The Facts on File Dictionary of Botany, page 84,
 * In the Filicales the leptosporangium has a specialized spore dispersal mechanism involving an annulus of cells with thick walls that ejects spores explosively as it dries out.