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.

The point is perhaps academic since the de la Grize family became extinct in the male line by the end of the 17th century, followed by the La Berthonnière at the end of the 18th.

Sources:

Arnaud, Etienne: RÉPERTOIRE DE GÉNÉALOGIES FRANÇAISES IMPRIMÈES,  éd. Berger-Levrault, Paris, 1979, Tome II, p.269

Beauchet-Filleau, H; de Chargè, Ch: DICTIONNAIRE HISTORIQUE ET GÉNÉALOGIQUE DES FAMILLES DU POITOU, 2me Èd. [Imprime Paul Oudin, Poitiers 1895], Tome II, p.671

Rietstap, J.B.: ARMORIAL GÉNÉRAL (2éme ed., G.B van Goor Zonen, Gouda 1884),  Tome I, p. 474