Spiraea hypericifolia subsp. hypericifolia

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1981, Flora Europaea. Volume 2. Rosaceae to Umbelliferae, Cambridge University Press : 5

(a) Subsp. hypericifolia :

Leaves narrowly elliptical, acute, entire. Sepals shorter than hypanthium; petals ovate, rather longer than stamens. Ukraine and S. Russia; one station in Bulgaria.