CELTIC SIGNS AND OGHAMS
BECAUSE OGHAM IS A SINGULAR WORD, RITE THE PLURAL OF WHICH IS OGHAMS
nope nope nope
Ogham is an Irish alphabet, and these letters are not the entire alphabet. The idea that ogham letters correspond to trees is a fallacy, perpetuated by “Druidic” orders of the 19th century.
there’s a wikipedia article on ogham that might help you.
The association with trees isn’t the fallacy, it’s the idea that tree ogam is the only sytem/associations the ogam have. The tree ogam is detailed in the Auraicept na n-Éces or “The Scholar’s Primer,” and In Lebor Ogaim, “The Book of Ogams” which are found in the Book of Ballymote. The Auraicept itself dates to around the twelfth century, although it’s possible the core of it could be as early as seventh century, and I think Lebor Ogaim is considerably later. It’s from Lebor Ogaim that we see hints that the ogam might have been used for divinatory purposes (using Fionn’s Window, perhaps). It’s possible that the idea might have been made up to make it all seem ye olde ogam and all mystical, because even then people liked to bullshit their way through stuff, just like Graves did later on with his ogham tree calendar and all that.
Although the tree ogham is the best known system, and the one detailed at length in the Auraicept, there are other kinds of system where the letters represent other kinds of things - colours are probably the best known alternative system, but there are also things like “sow ogham,” “church ogham” (with each letter representing a church in Ireland), “dog ogham” or a system where each letter represents a different kind of farming equipment. They might represent a code or secret language, a tally system, or maybe just a mnemonic, to help learn the alphabet.
You’re right, though, there are letters missing, and I’m not sure ‘reed’ is one of the original listings (I believe that one’s ngetal, which is translated as fern or broom by Calder). If I remember rightly, the ‘original’ ogam is believed to have been the twenty letters, with an additional five letters being added to the system at a later date. I’m guessing this is some sort of representation of Graves’ calendar/astrolgoical system, maybe? That certainly has no basis in history.
Damian McManus has a book called A Guide to Ogam that’s recently been re-released at a reasonable price. The run was probably quite limited so I’m not sure there will be any cheap copies left but it’s well worth a read if anyone’s serious about studying the ogam.