C. C. Hurst found that there were two distinct species passing as R. acicularis nipponensis.

One is a tetraploid that Hurst regarded as a subspecies of R. pendulina. This is the form with pendulous rimmed hips.

The other form (R. nipponensis of Crépin) is a diploid, which Hurst treated as a subspecies of R. rugosa.

R. acicularis nipponensis Willmott (non Crép.) (R. pendulina subsp) - tetraploid
R. acicularis nipponensis Crépin (R. rugosa subsp) - diploid