Petasites japonicus subsp. giganteus ("Akitabuki")

Japanese name: アキタブキ
Scientific name: Petasites japonicus subsp. giganteus

[Overview]
A perennial growing up to 2 m tall.
It extends long underground stems and forms new plantlets at their tips.
The leaves arise from the tips of the underground stems after flowering; they are reniform-orbicular, up to 1.5 m wide, with a deeply cordate base.
The leaf margins have minutely protruding teeth.
Young leaves have short curled hairs on the upper surface and cobwebby hairs on the underside, but later become hairless.
The petiole is up to 2 m long and is usually tinged with purple.
It is dioecious.
In the summer of the previous year, flower buds form at the tips of the underground stems and overwinter wrapped in the bases of the petioles and in scale-like bracts.
In early spring of the following year, before the leaves emerge, the flower buds wrapped in bracts appear as ovoid flower shoots (to).
The flower stalk is 100 cm tall and bears many white flower heads in a panicle.
The bracts on the flower stalk are oblong, 6.5–10 cm long.
The flower heads of male plants consist entirely of tubular bisexual flowers and do not set fruit.
The flower heads of female plants have many female flowers at the margin and bisexual flowers in the center, and set fruit.
The corolla of the female flowers is thread-like.
The fruit is a cylindrical achene with a white pappus.

[Uses]
The petioles and leaves are eaten.

[Notes]
The plant called Rawan-buki, found around the Rawan River in Ashoro, Hokkaido, reaches 3 m in height with stems 10 cm in diameter, and is designated a Hokkaido Heritage.
It is a local specialty of Ashoro.

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