Unazukitsukubane - Nodding Spring

...In the Tohoku region and along the Japan Sea coast, the plant is large and has wide leaves, but in southwestern Japan, the plant is small and has narrow leaves. In Shikoku, the Unazukitsukubane, which has drooping flowers, and the Yokoguratsukubane, which has short pedicels, have been differentiated and are sometimes distinguished as variants. The underground stem is thin and creeps horizontally. ...

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

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…東北地方や日本海側では植物体が大きく葉幅が広いが，西南日本では植物体が小さく葉幅が細いものが多い。四国には花が垂下するウナズキツクバネや花梗が短いヨコグラツクバネが分化していて，変種として区別されることがある。地下茎は細く横にはう。…

※「ウナズキツクバネ」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