This Leccinum has been found in several different Aspen groves at this location. The brown cap, lack of sterile margin, presence of hymenial cystidia (rare), and Aspen habitat led me to believe this might be Leccinum montanum. The spores seem to be the right size but the cystidia shape is not the same as specified by Thiers. The ones I have observed are fusoid to fusoid ventricose and often with a elongated apices.