Kalmar “Genus” kalma ce da ake amfani da ita a fannin ilmin halitta don rarrabawa da tsara halittu masu rai zuwa rukuni bisa la’akari da halayensu da kuma alakar juyin halitta. , wanda aka fi sani da tsire-tsire na corkscrew ko rush. Wadannan tsire-tsire na asali ne daga wurare masu dausayi da ciyayi a Afirka da Kudancin Amurka, kuma suna da siffofi na musamman kamar ganyayen karkashin kasa masu kamawa da kuma narkar da kananan shuke-shuken da ke cikin ruwa, da dunkulewar tsiron da ke taimaka wa tsirran su ratsa muhallinsu.