Asarum megacalyx T.Sugaw.
Aristolochiaceae
| Collection Number | Not collected |
| Collectors | (D. Boufford, C. Davidson, S. R. Christoph) |
| Identified By | D. Boufford |
| Source | C. Davidson |
| Date | 28 May 2016 |
| Country | Japan |
| region | Honshu |
| prefecture | Niigata |
| Location | Myoko-Togakushi Renzan National Park. Trail beginning at the south end of Sasagamine Dam (on Otomi Lake) through deciduous woods. 1275 m elev. |
| Lat/Long | N 36 51 04.5 E 138 4 30.8 |