According to Rod Tulloss, the name Amanita alba is not valid. It was originally used to apply to Amanita ovoidea. It has been generated by several authors since. Given the current status of knowledge of sect. Vaginatae in California, it is unclear what name to give it. “Amanita alba sensu Thiers” included white specimens of Amanita velosa…perhaps that is all it included. It would be necessary to go through all Thiers’ collections of “A. alba” in order to know. Rod recommended calling it “Amanita alba sensu auct. calif.” for the time being, so I have made that update. -Nathan (as admin)
many amanitas can produce white forms. an absence of color is insufficient to raise this to sp. status.
the top photo is clearly NOT velosa…those striations are waaaaaaay too long.
Amanita alba in the US is just a garbage can for white vaginate amanitas…which can occur anywhere and at any time and in any species.