Sylva Fibers

is the second of the 5 available fibers in the game. It is used for tailoring and alchemy. Gathering sylva fibers can only level the player's Plant Gathering level up to a maximum of 151. The plants have a chance of dropping Essential Mana, Idyllic Leafs Cochineal Beetles, Indigo Petals, Murex Snails, Saffron Stalks, or Purpurin Roots instead of the actual fibers.

Source
Dropped by monsters and plants from the following provinces:
 * Arcadia
 * Celestial Hills
 * Popolion
 * Vale of the Fang