Ohwi 1985 Flora of Japan

Japan Red List (2000): It is a perennial herb that grows under deciduous forest or on the edge of evergreen forests. Its scale stem, stem, leaves, and fruit are similar to those of the Hosoba kobai, but flowers are bell-shaped, and the nectar gland on the flower petals is located at one-third of the base. The style branches into three parts, and there are no small projections on the style or filaments. The flowering period is from March to April.

Of the 13 mesh populations, one mesh has gone extinct, and the status of another mesh is unknown. The remaining populations consist of a few individuals in one mesh, dozens in three meshes, and hundreds in six meshes, for a total estimated population of about 2,000 individuals. The average rate of decline is approximately 40%, and the probability of extinction in 100 years is around 90%. The main causes of decline are collecting for horticulture, abandonment of management, and deforestation [VU]