This beautiful group of flowers includes four varieties of Campanulas, commonly known as bellflowers. They species included are: C. lactiflora, C. rotundifolia Hostii, C. carpathica turbinata and C. carpathica alba. The illustration is from the Illustrated Dictionary of Gardening – A Practical and Scientific Encyclopaedia of Horticulture, edited by George Nicholson, circa 1885.
Here is a black and white clip art version of the group of flowers.
Click on images to enlarge.