rust (?) on rose

rust (?) on rose

Observation - rust (?) on rose - UK and Ireland. Description: A gall-type growth on a domestic rose bush in a garden. I'm not sure whether this was a bud or a leaf. Green, bulbous base, and curled, yellow outgrowth with flaky outgrowth. Could be a rust fungus, since it looks similar to the picture in http://www.exte

A gall-type growth on a domestic rose bush in a garden. I'm not sure whether this was a bud or a leaf. Green, bulbous base, and curled, yellow outgrowth with flaky outgrowth. Could be a rust fungus, since it looks similar to the picture in http://www.extension.umn.edu/projects/yardandgarden/YGLNews/images2/Jun152009/art3-3_600.jpg