Monographs Details: Mazus japonicus (Thunb.) Kuntze
Authority: Li, Hui-Lin. 1954. The Genus Mazus (Scrophulariaceae).

Lindernia japonica Thunb. Fl. Jap. 253. 1784.

Mazus rugosus Lour. Fl. Cochinch. 385. 1790.

Mazus vandellioides Hance in Walp. Ann. 3: 193. 1852.

This is a variable species with wide range of variations in its size, leaf shape, etc. I have interpreted broadly the scope of the species and have not attempted to divide it up subspecifically. Probably included in the concept is M. goodeniaefolius (Hornem.) Penn. which may be found in the southern warmer parts and which has been held in the species by most authors. Also some of the plants from Fukien and Chekiang are larger, more robust, and with more leafy stems. These plants may represent a distinct species, but as intermediate forms exist, it is not easy to delimit.