The early Medieval treatise ('The Scholars' Primer') describes the origin of alphabets from the Tower of Babel. It assigns plant names and meanings to the Ogham alphabet, to a lesser extent to Norse Younger Futhark runes, and by extension to Latin letters when used to write Gaelic. Robert Graves' book The White Goddess has been a major influence on assigning divinatory meanings to the tree symbolism. (See also Bríatharogam.) Some of the names differ from their modern equivalents (e.g. dair > darach, suil > seileach).
