What is the botanical name of the species that causes white rust of crucifers?

The association of fungi with the roots of higher plants is called:

Which group of fungi is commonly known as imperfect fungi?

$A$ facultative saprophyte is:

Gametangial copulation $(conjugation)$ is common in

There is a myth that immediately after heavy rains in forests, mushrooms appear in large numbers and form a very large ring or circle, which may be several metres in diameter. These are called as "fairy rings". Can you explain this phenomenon of fairy rings in biological terms? Discuss the mycelial structure in $Agaricus$ and its soil-borne nature.