Lepuropetalon and usually face upward. They are large compared to the rest of the plant, 2 to 3mm in diameter with male and female parts both present and functional. The calyx consists of five broad, often unequal sepals that are joined in the lower part to form a floral cup that encloses the lower half of the ovary and is thickened along its fissures to form five ribs. The sepals persist beyond the maturity of the fruit. The petals are scale-like, white and barely visible, on the rim of the floral cup between the sepals, or sometimes absent. They die but
Calyx of Held third postnatal weeks, around the time of hearing onset, the calyx of Held develops its characteristic, highly fenestrated (many openings) appearance. Fenestration results in the membrane being reduced to numerous small compartments, which increase surface area of the presynaptic cleft. As the membrane becomes increasingly pinched into these bulb-like structures, synaptic vesicles are further grouped into these spaces, resulting in an increased number of docked vesicles. To compensate for the available spaces in the calyx, glial cells with glutamate receptors and transports are used to fill open spaces, ensuring efficient uptake of glutamate in the synapse. This physical change in