what are the differences? They look identical to me... cuban royal: christmas: alexander: http://sawgrasslandscapemanagement.com/Palms.html
Stature for one thing, that and large clusters of red fruit in Winter. Alexander palm (Archontophoenix alexandrae )is much more slender and is frequently misidentified as Adonidia palm. http://floridagardener.com/palms/Veitchia_merrillii.htm http://www.pacsoa.org.au/palms/Archontophoenix/alexandrae.html