Assessments made over entire orchards on a single date may be inaccurate due to variation in catkin emergence between cultivars. Each individual staminate flower is composed of a central bract and two lateral bracteoles . From three to seven stamen develop in each staminate flower. The stamen is composed of the anther , where the pollen develops, and the filament , or stalk, which attaches it to the flower. In pecan, the filament is so short that it is inconspicuous.
Pollen is developed in the pollen sacs.
Shortly before dehiscence, the four pollen sacs fuse to form two chambers by the dissolution of the separating wall. The anther wall is two cell layers thick, with an outer epidermis and an inner endothecium . The opening of the anther is caused by drying and contraction of the outer layer in relation to the inner layer. Conversely, high humidity delays pollen dehiscence and extends the period of pistil receptivity. The time required for dehiscence under optimum conditions is summarized in Table 3.