Puccinia graminis tritici (fungus) causes black rust of wheat. It is a heteroecious parasite, ie, its life cycle completes within two hosts. Its dikaryotic phase completes on wheat plant (Triticum aestivum) which is also known as primary host, while its haplophase completes on leaves of barberry plant (Barberis vulgarise which is also known as secondary host. Urediospores (uredia) and teleutospores (telia) are formed on wheat leaves.