| Family | Hydrangeaceae (also placed in Saxifragaceae) |
| Subfamily | Hydrangeoideae |
| Tribe | Hydrangeae |
| Scientific name | Cardiandra alternifolia Siebold & Zuccarini |
| Synonyms | Hydrangea alternifolia Siebold |
| Common name | (Japanese common name) kusa-ajisai (クサアジサイ, 草紫陽花 [meaning: herbal Hydrangea]) |
| (English common name) none | |
| Distribution | (Japan) Honshu (south of Miyagi Prefecture), Shikoku, Kyushu |
| (Other nations) none | |
| Habitat | Mountane forest or forest edge |
| Chromosomal number | unknown |
| Description | Plants 20-70cm tall. Leaves 7-20cm long 3-6cm wide. Flowers 5 white petals each 3mm long, flowering in July to September. Perennial plants. |
| Reference | Cardiandra alternifolia Siebold & Zucc. |
| July 2007 at Mt. Tsukuba |
July 2007 at Mt. Tsukuba |
July 2007 at Mt. Tsukuba |
| July 2007 at Mt. Tsukuba |