VERTICILLATUM var. LITHOPHILOS H.Ohba, 1991
Distribution : Japan.
Differs from var. verticillatum :
Leaves opposite, petiolate, petioles 1 - 1.8 cm, lamina oblong, ovate, lanceolate or oblanceolate, 3 - 9 x 3 - 4.5 cm, shallowly crenulate with 6 - 8 teeth on each margin.