Kalmar "hydathode" tana nufin wani tsari na musamman na tsire-tsire, yawanci ana samuwa a kan tukwici ko gefuna na ganye, wanda ke fitar da ruwa mai yawa a cikin nau'i na ɗigon ruwa. Hydathodes sau da yawa suna shiga cikin guttation, wanda shine tsarin da tsire-tsire ke sakin ruwa mai yawa daga tushen. Kalmar "hydathode" ta samo asali ne daga kalmomin Helenanci "hydor" ma'ana "ruwa" da "hodos" ma'ana "hanyar" ko "hanya". Hydathodes suna taka muhimmiyar rawa wajen kiyaye daidaiton ruwa a cikin tsire-tsire kuma suna iya bambanta a cikin tsari da aiki a cikin nau'ikan tsirrai daban-daban.