This is the outer layer of the fungal node. It is blackish brown outside, white or greyish brown inside, and soft, loose, and elastic in texture. It is generally considered to be harmonious and neutral in nature, able only to promote urination and reduce edema; but it achieves this without exhausting the qi. It is more diuretic than Poria (Fu Ling), but less tonifying; it mobilizes the exterior to reduce subcutaneous edema.* (from Chinese Herbal Medicine Materia Medicia, 3rd ed).