The palm leaf (arborization) pattern that mid-cycle cervical mucus assumes when it is placed in a thin layer on a glass slide and allowed to dry. The pattern, caused by crystallization of the mucus as it dries, depends on the concentration of electrolytes, especially sodium chloride, which in turn depends on the amount of estrogen in the mucus. Smears of cervical mucus may be helpful in determining when a woman has ovulated. The mucus has a beaded pattern at other times in the menstrual cycle.