What a Broken Pattern Says About the Whole Set

The tree naming convention that gives ogham its popular identity holds for the original twenty letters with reasonable consistency, though even there scholars debate how much of it is a genuine mnemonic tradition and how much is a later gloss imposed by the grammarians who wrote it down. Or is useful precisely because it shows the convention breaking in real time. A scribe reaching for a word to carry a specific sound picked or, gold, a borrowed word with no botanical content, over inventing or straining toward a tree term that did not fit.

That single exception argues against reading the forfeda as tree letters in the same sense as the stone bound twenty. It argues for reading them as what the textual evidence actually shows: a scribal solution to a spelling gap, glossed after the fact with whatever word suited the sound, sometimes a tree and sometimes not. The four other forfeda do carry tree or shrub glosses, which keeps the appearance of the older convention intact for a reader moving quickly through the list. Or is the letter that stops a careful reader from assuming the appearance is the whole story, and a useful check against any modern chart that lists all twenty five ogham letters as trees without qualification.

Sources A Guide to OgamDamian McManus with Auraicept na n-Eces: The Scholars' PrimerGeorge Calder (ed.)