The Missimer Wildflower Preserve is a protected grassland in Napa County, California owned by the Land Trust of Napa County. The preserve is situated on considerable serpentine soil, leading to specially adapted native plants.[1] Situated within Snell Valley, the preserve is noted for its biodiversity of flora. An example of native wildflowers in the Snell Creek watershed is yellow mariposa lily, Calochortus luteus.