Palm Tree on a 90th degree apron from Memphis-Misraim
Palm trees can also be found on 52th degree Memphis Mirsraim tracing boards and regalia (“sage of the labyrinth”).
Feddersen (SO/16) has a German “Tempelmeister” tracing board from around 1860 with a variety of exotic symbols, including a palm tree (left, below the broken tower).
Here is also an image of the Royal Arch with a palm tree:
Also the Ancient and Accepted Scottish Rite knows palm trees (unfortunately unexplained in the description of this tracing board):
But, Maçonnerie des Hommes (1766, Vol. V. degree “Knight of the 12 Tribes”) does give an explanation:
You also see two palm trees, straight and high, their branches appear to stretch over the grave of master Hiram Abiff, the memorial that Solomon had raised in the Temple as a monument of the big man, in commemoration of his learning and virtues, etc.
The “Maitre Secret” (‘Secret Master’) in the Baylot collection refers to two palm trees in the middle of the tracing board, but with no further explanation.
Top and second: general Memphis-Misraim apron design
Second: Feddersen (Die Arbeitstafel in der Freimaurerei Band I (1982) SO/, p. 542) “Maurerisches Handbuch 1821 “Arbeitstafel der Tempelmeister; um 1860”
Third: General Ahiman Rezon by Daniel Sickels (1870)
Bottom: A.&.A.R. the Intermediate Degrees 1º – 17º G.E.W. Bridge (1974)