FOUND IT!
(
Eledhwen leaps up and down in ridiculous triumph)
From UT, "A description of
Numenor"
"...but only here grew the mighty golden tree
malinorne, reaching after five centuries a height scarce less than it achieved in Eressea itself. Its bark was silver and smooth, and its boughs somewhat upswept after the manner of the beech; but it never grew save with a single trunk. Its leaves,
like those of the beech but greater, were pale green above and beneath were silver, glistering in the sun; in the autumn they did not fall, but turned to pale gold. In the spring it bore golden blossom in clusters like a cherry, which bloomed on during the summer; and as soon as the flowers opened the leaves fell, so that through spring and summer a grove of malinorni was carpeted and roofed with gold, but its pillars were of grey silver. Its fruit was a nut with a silver shale; and some were given as a gift by Tar-Aldarion, the sixth King of Numenor, to King
Gil-galad of
Lindon. They did not take root in that land; but Gil-galad gave some to his kinswom an
Galadriel, and under her power they grew and flourished in thegarded land of
Lothlorien beside the River
Anduin, until the
High Elves at last left
Middle-Earth; but they did not reach teh height or girth of the great groves of Numenor."
The reason I remembered the shape was that I initially imagined they were shaped like cherry leaves, long with a single point, which turn a beautiful gold in Autumn. After reading the above my imagination got edited and the
Mallorn leaves got shorter.
