the Acacia plant

from my Masonic encyclopedia:

"An interesting and important symbol in Freemasonry. Botanically it is the Acacia vera of Tournefort, and the Mimosa nilotica of Linnaeus. It grew abundantly in the vacinity of Jarusalem, where it is still to be found, and is familiar in it's modern use as the tree from which the gum arabic of commerce is derived.

Oliver, it is true, says that "there is not the smallest trace of any tree of the kind growing so far north as Jarusalem," but this statement is refuted by the authority of Lieutenant Lynch, who saw it growing in great abundance in Jericho, and still further north. The rabbi Joseph Schwarz, who is excellent authority says: "The Acacia (Shittim) tree, Al Sunt, is found in Palestine of different varieties; it looks like the Mulberry tree, attains a great height, and has a hard wood. The gum which is obtained from it is gum arabic." Schwarz was for 16 yrs a resident of Palsetine, and wrote from personal observation. The testimony of Lynch and Schwarz should, therefore, forever settle the question of the existence of the acacia in Palestine.

The acacia, which in scripture, is always called Shittah, and in the plural, Shittim, was esteemed a sacred wood among the Hebrews. Of it Moses was ordered to make the tabernacle, the ark of the covenant, the table for the shewbread, and the rest of the sacred furniture. Isaiah, in recounting the promises of God's mercy to the Israelites on their return from the captibity, tells them that, among other things, he will plant in the wilderness, for their relief and refreshment, the cedar, the acacia (or as it is rendered in our common version, the shittah,) the fir, and other trees.

The 1st thing we notice is that it had always been consecrated from among the other trees of the forest by the sacred purposes to which it was devoted. By the Jew, the tree from whose wood the sanctuary of the tabernacle and the holy ark had been constructed would ever be more sacred than ordinary trees. The early Masons, therefore, very naturally appropriated this hollow plant to the equally sacred purpose of a symbol, which was to teach an important divine truth in all ages to come.

Having thus briefly disposed of the natural history of this plant, we may now exceed to examine it in it's symbolic relations.

First the acacia, in the mythic system of freemasonry, is preeminently the symbol of the immortality of the soul-- that important doctrine which it is the great design of the institution to teach. As the evanescent nature of the flower, which "commeth forth and is cut down," reminds us of the transitory nature of human life, so the perpetuation of the evergreen plant, which uninterruptedly presents the appearance of youth and vigor, is aptly compared to that spiritual life in which the soul, freed from corruptible campanionship of the body, shall enjoy an eternal spring and an immortal youth. Hence, in the impressive funeral service of our order, it is said that "this evergreen is an emblem, of our faith in the immortality of the soul. By this we are reminded that we have an immortal part within us, which shall survive the grave, and which shall never, never, never die." And again, in the closing sentences of the monitorial lecture of the 3rd degree, the same sentiment is repeated, and we are told that by "the evergreen and ever living sprig" the Mason is strengthened "with confidence and composure to look forward to a blessed immortality." Such an interpretation of the symbol is an easy and natural one; it suggests itself at once to the least reflective mind; and consequently, in some form or another, it is found to be existing in all ages and nations. It was an ancient custom,-- which is not, even now, altogether disused, -- for the mourners to carry in their hands at funerals a sprig of some evergreen, generally the cedar or the cypress, and to deposit in the grave of the deceased.

it goes on further and explains another use for the symbolism as innocence, and one of initation into the mysteries, but I don't feel like typing all of that out.