René Pomerleau (the great québecois mycologist) noted a couple of decades ago that he thought there was no taxonomic value in segregating the pallid specimens of A. brunnescens into var. pallida. On the A. brunnescens species page of the Amanita Studies web site, a picture from a single “fairy ring” shows the variation of cap pigment in brunnescens. The nearly pure white, slow staining, brunnescens-like entity goes under the name A. aestivalis Singer, at least for the moment.
Rod Tulloss