The portion of the fungus that grows closer to the root is white in color and is thus known as white poria; that closer to the outer skin is pinkish in color and known as red poria. White poria is the product that is normally dispensed when just Poria (fu ling) is prescribed. Penetrating the Mysteries of the Material Medica observes that the red variety "can only drain heat and mobilize water; it does not have the many actions of white poria." Red poria is often prescribed for such disorders as scanty, dark urine or urinary difficulty. Another way of looking at this is that white poria enters the qi aspect and red poria enters the blood aspect; white poria more strongly tonifies, while red poria is more facilitating. Thus for enriching the Heart and Spleen, and calming the Heart spirit, white poria is superior, but for eliminating water and dampness, especially if associated with blood stasis, red poria is the better choice.* (Chinese Herbal Materia Medica, 3rd edition).