Their leaves could also be lanceolate-oblong or elliptically shaped, with serrated margins.

The leaves' upper surface is hairless and is dark green in colour.

[4] The flowers open from July to September and are purple in colour.

They can be found growing in moist soils along roadsides, and are common in meadows and open woodlands.

The plant is self-incompatible and exhibits substantial ecotypic variation, a factor which may explain their broad geographic distribution.