Western Morning Glory

The Western Morning Glory (ニシアサガオ, Nishiasagao) is a poison that can make people fall asleep.

Background
Hayase used this to make March fall asleep for the Oniguma ritual. She also used this in Yanome to capture March, Fushi and Parona while unconscious.

It's also an ingredient to make Pillow Mochi according to an archive page in volume 2.