Synonym: Mazus japonicus
Mazus is a weedy annual with basal leaves and branches stems to 15 cm in height. The stems and leaves may be covered with short, retrorse-spreading hairs. The basal leaves are spatulate and up to 4 cm long and 1.5 cm wide. The margins have broad, rounded teeth. The stem leaves are smaller than the basal leaves
The inflorescence is a raceme of 4-10 flowers. The calyx is 4-5 mm long during flowering and up to 10 mm long in fruit. The individual calyx lobes are wide and taper gradually to a rounded point. The corolla is 7-10 mm long, blue-violet in color with yellow or white markings.
Mazus is a weedy species which may be found in moist lawns and bottomlands.
Mazus is a native of east Asia and has been introduced to the eastern United States and the metropolitan area of Portland, OR.
In the Columbia River Gorge, it may be found at river level as far east as Bonneville Dam.