The origin such as Southern Europe. It introduced from China to Japan old. (It is said that there is a cultivation history in 1000years. )
Grass seed is called, "Tonburi", and becomes medicinal use and for food. Shape,the color, and the tooth sitting dividing look like the caviare. (There is an alias with "Caviare of Japan", too. )｡ Special product of Akita. It uses it for the dressing thing and the vinegared dish, etc.
It is written "Houkigi (broom)" 「箒木（ほうきぎ）」 Houkigusa「箒草（ほうきぐさ）」 . The branch and stalk are dried and the broom is made.