Man's mugwort - Man's mugwort

A perennial herb of the Asteraceae family (APG classification: Asteraceae). The plant is hairless, and the stem is 0.4-1.4 m tall. It branches out somewhat at the top. The leaves are wedge-shaped, broad at the tip, and have some shallow serrations. The upper leaves are small, linear, and unserrated. There is a spatula-shaped rosette of leaves at the base, but these and the leaves at the bottom of the stem are usually dead by the time of flowering. From August to November, the panicle is formed at the top of the stem, and many flower heads are produced. The flower heads are small, ovate-globular or oblong-globular, 2 mm long and 1.5 mm wide. There are female florets at the edge of the flower head, and bisexual florets inside. The bisexual florets are sterile. The achene is oblong, 0.8 mm long, and glabrous. It grows in sunny mountainous areas throughout Japan and is widely distributed throughout East Asia. The name was given to this plant because the seeds are small and it was assumed that they were male plants that do not produce seeds, so it is called male mugwort.

[Hiroji Koyama February 18, 2022]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

キク科（APG分類：キク科）の多年草。全草に毛がなく、茎は高さ0.4～1.4メートル。上方で多少枝が出る。葉はくさび形で、先が広まり、いくつかの浅い鋸歯(きょし)がある。上部にある葉は小形の線形で鋸歯がない。根元にへら形のロゼット状の葉があるが、この葉と茎下部の葉は開花時には普通は枯れている。8～11月、茎上部に円錐(えんすい)花序をつくり、多数の頭花をつける。頭花は卵状球形または長楕円(ちょうだえん)状球形で、長さ2ミリメートル、幅1.5ミリメートルと小さい。頭花の縁(へり)に雌性の小花があり、中に両性の小花がある。両性の小花は不稔(ふねん)。痩果(そうか)は長楕円形で長さ0.8ミリメートル、無毛。日本全土の日当りのよい山地に生育し、東アジアに広く分布する。名は、種子が小さいので、種子をつくらない雄と思い、牡(おす)の蒿(よもぎ)とつけたという。

［小山博滋　2022年2月18日］

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