Triosteum

...A perennial herb of the honeysuckle family that grows in damp areas of plateaus (illustration). The opposite leaves are joined at the base, and the stem looks as if it is piercing the leaves, hence the name. The stem is upright and about 1m tall. The whole stem is densely covered with nectar glands and long hairs. The leaves are entire or wavy cut, and 10-20cm long. Flowers appear in the axils at the top of the stems, 1-3 at a time, in May-June. The corolla is tubular-bell-shaped, 2.5cm long, pale yellow-green, with purple-brown interiors. The ovary is inferior and has 4 lobes, one of which degenerates. The fruit is oval-shaped, about 1cm long, and has a 5-lobed calyx. ...

*Some of the terminology explanations that mention "Triosteum" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…高原の湿ったところにはえるスイカズラ科の多年草（イラスト）。対生する葉が基部で合着し，茎が葉を突き抜いているようなのでこの名がある。茎は直立し，高さ約1m。全体にみつ腺や長い毛が密生する。葉は全縁または波状に切れ込み，長さ10～20cm。花は5～6月に茎の上部の葉腋（ようえき）に1～3個ずつつく。花冠は筒状鐘形，長さ2.5cm，淡黄緑色で内側は紫褐色。子房は下位，4室でうち1室は退化する。果実は長さ1cmくらいの卵球形，5裂した萼が残る。…

※「Triosteum」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報