title: Positional information and pattern regulation in hydra: the formation of boundary regions following axial grafts.
mesh_terms: D000818:Animals; D006829:Hydra / Q000254:growth & development* / Q000502:physiology; D008954:Models, Biological; D009024:Morphogenesis; D009949:Orientation; D012038:Regeneration; D013217:Starvation