de La Court de la Grize
This was the coat of arms of de La Court de la Grize, of Poitiers. Influenced by the Abbé M. de Vertot, a number of heraldic authors, including Rietstap, mistook these arms for the La Berthonnière arms.
The de la Grize blazon reads Arg three mullets gu arranged 2 and 1, and on a chief three mullets counterchanged. The researches made by Beauchet-Filleau in the second half of the 19th century in the Poitou region of France indicate however that the Berthonnière arms consist of a gold bend charged with a porcupine, all on a green field.