Black moss

1823, Agriculture, article in (editor), Encyclopaedia Britannica, 6th Edition, Volume 1, page 373, There are, however, two general kinds of mosses; black moss, and whitish or yellow moss. The black moss is originally of a mahogany colour, but speedily becomes black upon exposure to the air.

Black moss, also known as seaweed hair, looks like fine black hair. The name of the ingredient in Cantonese, fat choy, is the same as the New Year's greeting, Gung Hay Fat Choy, so it has an auspicious meaning and symbolizes prosperity.