''P. cablin'' .
*Erect or ascending aromatic herb, up to 1 m tall. Stem branched, solid, angular, tomentose.
*Leaves decussately opposite, thin- or thick-membranaceous, with short appressed hairs; petiole 1-3(-8) cm long; blade ovate, 5-10(-14) cm × 3.5-6.5(-10) cm, base cuneate, margin simple or double crenate-serrate, apex acute, gland-dotted below.
''P. heyneanus'' .
*Erect or ascending, aromatic subshrub, up to 1.5 m tall. Stem branched, slender, solid, obtusely 4-angular, subglabrous and rooting at the base, short-haired in upper part.
*Leaves decussately opposite, thin-membranaceous, subglabrous to rather densely soft-haired; petiole 1-6 cm long; blade ovate, 1-14 cm × 1-8 cm, base cuneate, margin simple or double crenate-serrate, apex acuminate, gland-dotted below.