Gysahl Green is a kind of plant found in Plains biomes, and can be used to tame Chocobos for riding, heal injured Chocobos for 5 hearts, mixed in with the cake's reicipe to make Gysahl Cakes, and used with Sugar to make Gysahl Raw Pickles.
2. Find some Gysahl Greens then make them into seeds (Crafting recipe above)
3. Plant the seeds in the tilled and watered dirt and you are now the proud owner of a Gysahl Green farm!
4. When they are fully grown they will look like they did when you found them, red part above ground. To harvest a Gysahl just break it. When harvesting you can get 4 different things: Gysahl Seeds, Gysahl Greens, Loverly Gysahls, Or a Golden Gysahl.
Gysahl Greens (and Chocobos) are from Final Fantasy.