sentences:  A 2007 field study on four species of boletes revealed little correlation between the abundance of fruit bodies and presence of its mycelia below ground, even when soil samples were taken from directly beneath the mushroom; the study concluded that the triggers leading to formation of mycorrhizae and production of the fruit bodies appear to be more complex than previously thought.In the past the fungus had been reported in China.However, recent molecular studies show that Asian porcini appear to belong to different species.