Actaully found enough of these this year, that people were able to compare these with B. chrysenteron, and you can tell the difference. Mostly it is in the feel of the pileus, which is thicker and plasticy fealing in the zelleri, and thiner and velvet feeling in the chrysenteron. Also the zelleri is completely red in the stipe, more yellow in the pores, less likely to have cracks in the cap.