Japanese name: オオカワヂシャ（大川萵苣） Scientific name:Veronica anagallis-aquatica
[Overview]
A biennial 0.3–1 m tall, found at sunny waterside sites and in wetlands.
It has creeping rhizomes.
The stems and leaves are fleshy, soft and hairless.
The leaves are simple and opposite, oblong to lanceolate, 3–7 cm long and 1–2 cm wide, with a sharply pointed tip; the leaf margin has serrations, but they are indistinct and the margin looks almost entire.
The leaf base clasps the stem.
Racemes arise from the upper leaf axils of the stem and bear many flowers.
The corolla is 4-lobed, 5 mm across and pale purple.
The fruit is a spherical capsule; the fruit stalk is horizontal at flowering but points obliquely upward at fruiting.
It can be distinguished from the native Kawajisha by whether the leaf serrations are distinct.
[History]
The first specimen was collected in Kanagawa in 1867.
[Notes]
It is designated a "Specified Invasive Alien Species" under the Invasive Alien Species Act.
