Vere Foster's simple lessons in water-color, flowers : eight facsimiles of original water-color drawings and numerous outline drawings of flowers, after various artists, with full instructions for drawing and painting (1884)
Foster, Vere, 1819-1900 · London : Blackie & Son · leaf 50
required, in three or four distinct stages all over the drawing, great pains being taken not to overdo the quantity or depth of any tint. Recollect to leave the undertint where required to indicate the veins and texture of surface. If there be any difficulty in doing the painting of any part it… … Common Primrose.
Watercolor painting
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.