In order to use Imperata cylindrica (Chigaya) for the conservation and creation of the environment, current studie son Imperata cylindric ain taxonomy, autoecology, phytosociology, weed science, agrostology etc. are reviewed and discussed. Imperata cylindrica is a harmful weed widely distributed from the tropical zone to the temperate zone of the world. In Japan, the range of the species is from Okinawa to Hokkaido. The speciesis divided into two varieties based on the presence or absence of hairs on the node of culm. One is var. koenigi iand the other is var. cylindrica .Imperata cylindric atype grassland are classifie dinto five phytosociologica lclasses ,Miscanthetea sinesis, Glehnietea littorali sV,iticetea rotundifoliae ,Artemisietea principis and Chenopodietea. Imperata cylindric agrassland belonging to Miscanthetea sinensis are developed on embankment slopes, river terraces, roadside along paddy fields etc. where weeding by cutting is carried out two or three times a year. This weeding grassland is reported as a new community , Imperata cylindrica― Erigeron annuus community which is characterized by the presence of Erigeron annuus, Ixeris dentata et al. It seems that this community is available as soil binder on embankment slopes, a model of wild flowers for landscaping and as grassland biotope
