I just checked in the current Sunset National Guide and they list it as Feijoa sellowiana with an aka of Pineapple Guava and, alternatively, Acca sellowiana - but they have no listing for the Acca. Also, unlike the db entry listing here that shows height to be 8-10', the Sunset Guide lists it as 18-25' tall and wide (which is what I remember it to be when grown as a tree). So, it will remain Feijoa to me
