Kalmar "class Musci" tana nufin rarrabuwa taxonomic ga rukuni na tsire-tsire marasa jijiyoyin jini waɗanda aka fi sani da mosses. Mosses ƙanana ne, tsire-tsire masu laushi waɗanda galibi suna girma a cikin dunƙule masu yawa ko tabarmi a cikin ɗanɗano ko wurare masu inuwa. Suna haifuwa ta spores kuma ba su da tushen gaskiya, mai tushe, ko ganyaye. Ajin Musci wani bangare ne na rabon Bryophyta, wanda kuma ya hada da hanta da kaho.