Amsinckia grandiflora is a species of fiddleneck known by the common name large-flowered fiddleneck. This is a wildflower endemic to California and considered a Critically endangered species on the state and national level. The last remaining native populations are on the grasslands near Lawrence Livermore National Laboratory in Alameda County, California. Other populations have been established in nearby protected areas. The plant is endangered due to a number of factors, including invasive plants, grazing, and development of the valuable land. The last remaining native populations are on the grasslands near Lawrence Livermore National Laboratory in Alameda County, California. Other populations have been established in nearby protected areas. The plant is endangered due to a number of factors, including invasive plants, grazing, and development of the valuable land. This fiddleneck has low reproductive output; it produces few seeds per plant. It is also heterostylous, making the plant self-incompatible, which means individuals cannot breed with other individuals of the same morph. This often prevents reproduction. This fiddleneck is also sensitive to habitat; it grows on sedimentary loam in mesic areas of its range. The Livermore Laboratory is actively monitoring the status of this California endemic.