Blue willow - Blue willow

An evergreen shrub of the Solanaceae family (APG classification: Solanaceae). Its name comes from the fact that its leaves resemble those of a willow and that it blooms pale purple flowers. Native to southern Brazil, northern Argentina, and Uruguay, it was introduced to Japan via the Ryukyu Islands at the end of the Edo period, and is therefore also known as the Ryukyu willow. The leaves are alternate, oblong-lanceolate, 12-15 cm long, 2-4 cm wide, pointed at both ends, without sawtooth edges, and whitish-green on both sides. In July and August, it produces a cone-shaped inflorescence at the top of the stem, with many pale purple flowers that bloom downward. The flower diameter is about 2.5 cm, the corolla is cup-shaped with five deep lobes, and the lobes are egg-shaped elliptical. It has one pistil, and five stamens stand upright around it. The fruit is egg-shaped, liquid-like, and ripens to a purple-black color, but only in warm climates. It is cultivated in the Kanto region and west of Honshu, and grows well in sunny, sandy loam soil. It is propagated by dividing the plant.

[Yoshio Kobayashi July 16, 2021]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

ナス科（APG分類：ナス科）の常緑低木。名は、葉がヤナギの葉に似ており、淡紫色の花を開くことによる。ブラジル南部、アルゼンチン北部、ウルグアイ原産で、江戸末期に琉球(りゅうきゅう)を経て渡来したのでリュウキュウヤナギともいう。葉は互生し、長楕円(ちょうだえん)状披針(ひしん)形、長さ12～15センチメートル、幅2～4センチメートル、両端がとがり、縁(へり)に鋸歯(きょし)はなく、両面とも白緑色。7～8月、茎の上部に円錐(えんすい)状の花序をつけ、多数の淡紫花を下向きに開く。花径約2.5センチメートル、花冠は杯状で深く5裂し、裂片は卵状楕円形である。雌しべは1本。周りに5本の雄しべが直立する。果実は卵状球形、液質で紫黒色に熟すが、暖地でないと結実しない。本州の関東地方以西で栽培され、日当りのよい砂質壌土でよく育つ。繁殖は株分けによる。

［小林義雄　2021年7月16日］

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