Japanese name: タチアザミ（立薊） Scientific name:Cirsium inundatum
[Overview]
A perennial 1–2 m tall, growing in wetlands and along streams from the mountains to the subalpine zone.
The stem is erect and branches in the upper part.
The upper part of the stem bears sparse brown hairs and cobwebby hairs.
There are basal leaves and stem leaves; the basal leaves and the lower stem leaves have withered by the flowering season.
The stem leaves are alternate; those at the middle of the stem are lanceolate to ovate, 15–25 cm long and 4–14 cm wide, and are either pinnately divided into 4–5 pairs of lobes, or undivided with toothed or nearly entire margins.
The leaf margins have spines, and the base clasps the stem with ear-shaped lobes.
The flower heads are borne at the stem tip in corymbs or in dense clusters of about 2–5, facing upward; they are pale reddish purple, with slender stalks 0.5–3 cm long.
The involucre is bell-shaped, green, 1.6–2 cm long and 1.2–1.5 cm wide, and the involucral bracts are in 6–7 rows and not sticky.
The involucral bracts are hard, needle-like with a flat cross-section, and ascending.
The fruit is an achene with a white pappus.
