Caltha natans
Caltha natans is a species of flowering plant in the buttercup family. It goes by the common name floating marsh marigold.
Description
Caltha natans is an aquatic herbaceous perennial that is insect pollinated. Unlike other species of Caltha that are found in North America, C. natans shows relatively little morphological variation, and has not been divided into infraspecific taxa. The plants typically grow in shallow water, with floating leaves up to wide and long, on a petiole up to long. The flowers are roughly in diameter and have five white or pinkish sepals; they are produced in late spring. Each flower forms 20–55 follicles, which contain black, elliptic seeds in diameter.Distribution
Caltha natans has an amphi-Beringian distribution, being found in both North America and East Asia. In Asia, it is found in Siberia, Mongolia, and the Chinese provinces of Heilongjiang and Nei Mongol. In North America, it is found in Alaska, the Canadian provinces of British Columbia, North West Territories, Yukon, Saskatchewan, Alberta, Manitoba, and Ontario, and in a small part of the contiguous United States.In Minnesota, it is listed as a threatened species, it is generally rare or very localized throughout its native range in North America. It has only been found a few times south of the Canadian boarder and a number of these locations have been wiped out by habitat loss.