Prolonged heat allows the mycelium, or fibrous root-system, to grow large and strong, so that when rain comes and the temperature falls, the plant has the energy to throw up fruit above ground level.
After the prolonged heat of 1976, whole fields literally turned white when rain at last fell in September. But without sufficient warmth all activity remains subterranean.
Even if we now get a heatwave, it may be too late. But dedicated fungus hunters never give up, and much remains mysterious about their quarry.
Why do mushrooms always seem to grow in some fields, or parts of fields, and not in others? Why are some immediately infested with worms, which eat their way up the stalk, while others remain deliciously intact? Height above sea-level, inclination (to north, south, east or west), sun and shade seem to make little difference.
One traditional belief is that mushrooms thrive on stallions' droppings - and this is probably because stallions, like donkeys, habitually dung on one spot, thus creating concentrated deposits of manure.