This plant has been identified by J.B. Phipps (University of Western Ontario) as being Crataegus irrasa.
As seen in the photo it has 20 white anthers which is what brought it to my attention. It is located at the roadside across from the north entrance to Stonewyck (Trailer) Park in Georgian Bluffs. I believe there is another plant of the same species located east of Holland Centre. Herbarium specimens of both these plants have been deposited at the ROM