Rosa gymnocarpa dwarf rose 

Rosa gymnocarpa dwarf rose---bud

Rosa gymnocarpa dwarf rose

Information from USDA Plants Database 

http://plants.usda.gov/java/profile?symbol=rogy

https://www.google.com/search?q=Rosa+gymnocarpa+dwarf+rose&hl=en&source=lnms&tbm=isch&sa=X&ei=pQZLUaeWG8XUiwKZvoCQBQ&sqi=2&ved=0CAcQ_AUoAQ&biw=1008&bih=522