All trade with Germany totally ceased during that time.
Amanda said it appears that her great great grandparents were immigrants from Germany.
Founded in 1886, they were importers of china and glass from Europe.
Perhaps the painter was just trying to identify it on his/her own as having done the work for appears to have been a brand name used for marketing and exporting china.
They most likely special ordered their china from one of the German factories such as Schumann or Rosenthal who actually produced, decorated, and personalized it for , a decorating studio in business from 1869-1949 in Dresden, Germany.
They also had a decorating studio in Limoges, France. My speculation is that this overglaze green stamp was provided for application on the whiteware after decoration with the flower pattern that was copied by the artists. This appears to be the stamp of the manufacturer of the board/paper used by artists for their creations.
Pattern name is Stamped label written in French which appears to say something about "Honorable Mention at Exposition Universelle of 1855, Papier, Carton, Chassis, Toiles, Anti-Ponce pour le Pastel, P. Apparently, he was given honorable mention for his products at the1855 Exposition.Please be sure to tell us how you would like to be acknowledged for your contributions -- by full name or by initials only, or even anonymous, although we do prefer first and last names.We also like to know your general location such as city, state, country, region, etc.It dates back to somewhere between the years of 18, based on the date of the mark.for this particular cartouche mark; however, those were the years we were at war with Germany.Found on back of a 19th Century French Pastel Portrait by M. Kimball, a documented American Artist who exhibited a portrait drawing in a Paris Salon in 1886. This is a modern-day mark, probably a decorating mark, and is said to have been used after 1993.