sessile
adjective uk/ˈses.aɪl/ us/ˈses.əl/
（花，叶等）无蒂的;无柄的
used to refer to a leaf or flower that has no stem of its own but is attached directly to the main stem of the plant
（动物）固着的
used to refer to animals that are permanently attached to one spot and cannot move around
sessile sponges 固着海绵动物