Yelva Petrea Sophie Vermehren, born February 13, 1878 in Helsingborg, died unknown year, was a Swedish-Danish painter. She was the daughter of the wholesaler Johan Carl Emil Bock and Nanna Oline Christiane Augustinus. She married the Danish artist Sophus Vermehren in 1901 but the marriage ended in divorce. She studied at Voss tegnskole, Wermehren's art school in Copenhagen and at Teknisk Skole in Odense as well as with Valdemar Irminger at Det Kongelige Danske Kunstakademie 1905–1910. Separately, she exhibited in Copenhagen in 1914 and she participated in the Charlottenborg exhibitions 1912–1914 and the November exhibition in Copenhagen in 1927 and 1930. Her art consists exclusively of flower still lifes.