BIFF 1 Brush
These new combination brushes are great for doing wet or dry style tree trunks, thick vines, and texture strokes for mountains, rocks and cliffs.  They feature a compact multitude of short stiff hairs that give the brush a lot of body.  When the bristles spread, they turn punk-rocker.  You can strike your paper to create spectacular foliage, moss, and all kinds of coarse texture effortlessly.