Diomedian scarlet moss was a feathery, bright red plant native to the Diomedian system, which reproduced from spores. It was difficult to cultivate, and so was sometimes taken on as a challenge by botanists.
Doctor Beverly Crusher grew a number of Diomedian scarlet moss as part of her hobby in 2367. When the USS Enterprise-D passed through an unstable wormhole in the Ngame Nebula and the crew was apparently rendered unconscious for thirty seconds, Crusher discovered that in fact they had lost an entire day, from the amount of growth in her moss cultures. (TNG: "Clues")