Narcissus (plant) corona. Floral tubes can range from long and narrow in sections "Apodanthi" and "Jonquilla" to rudimentary ("N. cavanillesii"). Surrounding the floral tube and corona and reflexed (bent back) from the rest of the perianth are the six spreading tepals or floral leaves, in two whorls which may be distally ascending, reflexed (folded back), or lanceolate. Like many monocotyledons, the perianth is homochlamydeous, that is undifferentiated into separate calyx (sepals) and corolla (petals), but rather has six tepals. The three outer tepal segments may be considered sepals, and the three inner segments petals. The transition point between the floral tube and
Calyx of Held MNTB neurons to reach the SOC approximately 0.2 ms following the initial cochlear excitation. This ~0.2 second time measurement is important for comparing the contralateral (opposite side) and ipsilateral (same side) stimulation necessary in sound localization in the horizontal plane, and is key in distinguishing the location of low frequency sounds. For every principal neuron there is one calyx, and for most GBC axons there is only a single calyx, although there are exceptions to this pairing. This in general creates a one-to-one ratio between GBCs, the calyces of Held, and the principal neurons. The calyx of Held encompasses the