Japanese name: オオバナミズキンバイ（大花水金梅） Scientific name:Ludwigia grandiflora subsp. grandiflora
[Overview]
An aquatic perennial, but it also grows on land.
In its aquatic form it grows densely in mats on the water surface.
On land, the stems are covered with soft hairs; the lower part creeps along the ground and the tip rises to a height of 0.3–0.8 cm.
The submerged leaves are simple, borne in rosettes, and ovate to obovate.
The aerial leaves are simple and alternate, elliptic to lanceolate, with soft hairs on both surfaces and along the margins.
The leaf margins are entire.
Flowers are solitary in the leaf axils, yellow, 5–6-petaled, 2–5 cm across.
The fruit is a cylindrical capsule, with the sepals remaining at the top at first.
The fruit has a woody endocarp, and the seeds are enclosed in the endocarp.
[History]
It is thought to have escaped from plants introduced for aquariums, and is naturalized mainly in the Kinki region.
[Notes]
It is designated a "Specified Invasive Alien Species" under the Invasive Alien Species Act.
It regenerates even from fragments of leaves and stems and has vigorous growth.
