Amanda Almira Newton made four illustrations of Marsh Seedless grapefruits in 1912, according to USDA's Pomological Watercolor Collection website (
https://pomological.art/).
The illustration that appears as the third to last illustration (between Dedication and Acknowledgment) in this post has dates of May 16, 1912, and May 25, 1912, and is numbered as 56454 in the collection. The model for the illustration was borne on "Tree 111" at the Dixon Ranch in Riverside CA.
Two of Newton's other Marsh Seedless grapefruit illustrations dated 1912 also source from the Dixon Ranch. Illustration 56421 derives from "Tree 101." The illustration has dates of May 13, 1912, and May 18, 1912.
The other Dixon Ranch-originating illustration (56449) was associated with "Tree 106." The illustration has dates of May 16, 1912, and June 20, 1912.
Newton's fourth 1912-produced Marsh Seedless grapefruit illustration (99993) depicts a grapefruit from Arizona, with a date of April 25, 1921.