Heterocodon is a monotypic genus of plants in the bellflower family containing the single species Heterocodon rariflorum, which is known by the common names rareflower heterocodon and western pearlflower. It is native to western North America from British Columbia to California to Colorado, where it emerges during the spring in wet areas such as meadows. This is an annual herb producing a very thin, erect stem to 30 centimeters in maximum height.