This class contains the fungi considered to be mushrooms, shelf fungi, puffballs, stinkhorns, bird's nest fungi, jelly fungi, and the plant pathogens the rusts and the smuts. Most are saprophytes, but some associate symbiotically with plants while others are pathogenic. The hyphae are narrower than the Zygomycota and typically septate (dolipore septum). Meiotic basidiospores are formed externally on the differentiated hyphal tips (basidia),which are usually the site of nuclear fusion and meiosis. They have a prolonged binucleate dikaryotic stage, which is maintained by use of clamp connection. The members of this class have a well developed mycellium, produce basidiospores on basidium or on the germinated teliospores.