Generally, physical dormancy is the result of one or more palisade layers in the fruit or seed coat. These layers are lignified with malpighian cells tightly packed together and impregnated with water-repellent. In the families Anacardiaceae and Nelumbonaceae the seed coat is not well developed. Therefore, palisade layers in the fruit perform the functional role of preventing water uptake . While physical dormancy is a common feature, several species in these families do not have physical dormancy or produce non-dormant seeds.