Shrubs

Shrubs appear in large amounts in forests. Little else is known about them.

Dead Shrubs
Dead Shrubs is a block that was added in beta 1.6. It spawns on Sand blocks in the desert biome. Dead shrubs are not a solid block, but rather an aesthetic weed that does not block movements, like Sugar Cane, Wheat and Tall Grass; just occurring naturally.

Dead shrubs currently have no use, and cannot be replanted. They behave similarly to normal Saplings, but when you try to use Bone Meal on it nothing will happen.

Screenshot
http://i.imgur.com/b0Kno.png another pic