An unusual Martin Brothers stoneware flask by Robert Wallace Martin

An unusual Martin Brothers stoneware flask by Robert Wallace Martin, twin-handled form with flattened back, incised with a panel of a hummingbird and butterfly before grasses, the back with a bird perched amongst berried bough, in shades of brown and ochre on a buff ground incised R W Martin & Bros London & Southall, firing hairlines to body 18.5cm. high