Lactarius chrysorrheus

It's perfectly circle.

Lactarius chrysorrheus - http://www.errotari.com/Micologia/especie.php?1674 Comments: This species is of medium size and has a hat coloration ranging from orange-brown and yellowish brown color with flecks of intense concentric zones may form especially towards the edge. And foot plates with orange or whitish bumps. The white latex is quickly turning bright yellow, very spicy. Can be easily confused, seen from above, with species of Lactarius deliciosus group that secrete latex orange or wine. Inedible due to its pungent flavor. Ecology: It can appear on all summer but in autumn, form small groups and can be found more often in oak or chestnut and occasionally in pine, is common.

I would say this is Lactarius deliciosus, because Lactarius piperatus is all white.