Vintage Royal Crownford - England cup or stein. This is marked 'ironstone', but it's not anything like antique English ironstone porcelain - it's a 20th century vintage ceramic, like mid-century 'ironstone' dinnerware.
That being said, this piece is gorgeous! We love the black toile style floral with the deep mustard gold background.
It's about 6 1/4" tall overall, nicely sized for a vase. There's a tight hairline to the rim, but it doesn't look as though it would be a problem with occasional use. And no problem at all with fake flowers!