This is a superb oil painting on board by Bronwen Roberts (1917 - 2017,) a Welsh artist represented in the Museum of Modern Art, Machynlleth. It features a beautiful still life of white californian poppies in a jug; white flowers being a favourite subject of the artist. It's painted in a semi-abstract style that represents Roberts' mature style; it's recognisably by the same artist as those in the Museum. You can see them on the Museum's website, and also on ArtUK. The style is similar, with loose and dynamic brushwork, the images drawn first with lies of black paint, then brought to life with broad strokes of colour; however in this painting the technique pushes the work away from the representational into almost abstract territory - a difficult act to pull off. The palette is also more restrained. This almost certainly dates it as later than the museum paintings, probably one of her later works. There are no others on the internet that I can find, the rest being probably in private collections.