Hangesho (the eleventh day after the Summer solstice) is one of the seasonal days (zassetsu) in the Japanese calendar and is so-called because it falls around the time that the medicinal herb Lizard's Tail (Crowdipper) flowers (the leaves of the hangesho (also called katashirogusa) also turn white on half the leaf around this time).
半夏生（はんげしょう）は雑節の一つで、半夏（カラスビシャク）という薬草が生えるころ（ハンゲショウ（カタシログサ）という草の葉が名前の通り半分白くなって化粧しているようになるころとも）。