B
Beth
 Birch

L

Luis

 Rowan

N

Nion

 Ash

F

Fearn

 Alder

S

Saille

 Willow

H

Uath

 Hawthorn

D

Duir

 Oak

T

Tinne

 Holly

C

Coll

 Hazel

M

Muin

 Vine

G

Gort

 Ivy

P

Pethboc

 Dwarf Elder

R

Ruis

 Elder

A

Ailm

 Silver Fir

O

Onn

 Furze

U

Ur

 Heather

E

Eadha

 White Poplar

I

Idho

 Yew
"... The names of the letters in the modern Irish alphabet are also those of trees, and most of them correspond with O'Flaherty's list, though T has become gorse; O, broom; and A, elm.

I noticed almost at once that the consonants of this alphabet form a calendar of seasonal tree-magic, and that all the trees figure prominently in European folklore ..." (The White Goddess)