Minecraft wiki entry for Development_versions, associated text: Added cornflower.
Gives blue dye.
Appears in plains biomes.
Added wither rose.
Gives black dye.
Inflicts 1 second of Wither status to players and mobs around it.
Can be dropped or planted from any non-undead mob being killed by the wither.
Added lily of the valley.
Gives white dye.
Appears in forest biomes.