A prosthesis is disclosed for placement across an ostium opening from a main body lumen to a branch body lumen. The prosthesis comprises a radially expansible support, at least two axially elongate longitudinal members, at least one of which can be fronds, extending from an end of the support, and a circumferential member connected to at least one axially elongate longitudinal member and unconnected to at least one other axially elongate longitudinal member.