Angelica acutiloba with distinct calyx and white corolla. However, the calyx is often reduced with obsolete calyx teeth. The flowers have five petals, sepals, and stamens. The white petals are often obovate to oblong. The inflorescences contain fifteen to forty-five pubescent rays, 1–10 cm in length, which surround about thirty small disk flowers. The peduncles which hold the entire inflorescence are glabrous or pubescent and 5–20 cm long. While the stalks of each single flower in the flower clusters called pedicels, are thin and often sessile. The whorl of bracts beneath the inflorescences is called involucre. It consists of phyllaries, modified bracts,
Calyx of Held high frequency sound localization. This synapse has been described as the largest in the brain. The related endbulb of Held is also a large axon terminal smaller synapse (15-30 µm in diameter) found in other auditory brainstem structures, namely the cochlear nucleus. As with the calyces, these synapses promote fast, efficient information transfer. The calyx of Held holds vesicles containing glutamate on the presynaptic terminal, the vesicles are released upon stimulation (originating in the auditory system). The glutamate then binds to two known glutamate receptors, AMPA- and NMDA receptors. Commonly used in research due to its large size, the calyx