Art Pottery Vase - signed

I picked up this beauty at the Alameda Flea Mkt today. i just love the colors and the glaze drip design. it's signed on the bottom '591' and an impressed maker's mark which i cannot read. can anyone else make it out or do you recognize it? the large number may be a sign that it's a European piece, but the sloppy glaze on the bottom makes me think it's American. any thoughts appreciated. the piece is 10 inches tall and i found it in Alameda, CA. thank you!