In addition to the confusion with Refosco, some plantings of Mondeuse noire in the Russian River Valley were discovered to actually be an offspring of Mondeuse noire, Calzin.
Additionally, there was a mix-up regarding Refosco; it was found that some plantations of Mondeuse noire in the Russian River Valley are actually a cross between Mondeuse noire and another grape variety, possibly Calzin.