This is a Persian Buttercup, also known as Ranunculus asiaticus. I spent most of my life having no clue this flower existed, until Pinterest and many bloggers started obsessing over them. They are crazy beautiful and very similar to roses. They also have hollow, very floppy stems that do NOT hold up well to handling and close inspection while painting. Now I know.
This colour is "Sunset Orange", and it came from I Fiori in Hamilton. Bev had all kinds of interesting looking inspirations for me... I can tell that I'm just going to have to move into her store.