Margaret Gere (August 23, 1878-1965) was a British painter, notably in tempera. She and her sister Edith, who married artist Henry Payne, were known as “the masterful Miss Geres”.
Biography on Wikipedia: https://en.wikipedia.org/wiki/Margaret_Gere

Italian Piazza by Margaret Gere
1913 / Watercolor and gouache / 14-1/2″x10-1/2″ / Private collection

Margaret Gere on Artnet: http://www.artnet.com/artists/margaret-gere/

More links:
https://www.tate.org.uk/art/artists/margaret-gere-1154
https://artuk.org/discover/artists/gere-margaret-18781965
https://sarahcolegrave.co.uk/artists/margaretgere