Melampyrum laxum Miq. var. yakusimense (Tuyama) Kitam.

Family: Orobanchaceae
Japanese: ヤクシマママコナ (屋久島継粉菜) [Yakushima Mamakona]

The annual reappearance of spreads of this species in the hemiparasytic Melampyrum genus gives the impression of something from a meadow—or perhaps inner-city weeds—along the trail and near the peaks of intermediate mountains.

References:
新版　屋久島の植物 川原勝征,初島住彦(監修),2001：南方新社
米倉浩司・梶田忠 (2003-)　「BG Plants 和名－学名インデックス」（YList），http://ylist.info（ 2019年8月14日）