Glossary of plant morphology others may form a tight spiral, or whorl, around the flower stem. First, at the base, are those non-reproductive structures involved in protecting the flower when it is still a bud, the sepals, then are those parts that play a role in attracting pollinators and are typically coloured, the petals, which together with the sepals make up the perianth (perigon, perigonium). If the perianth is differentiated, the outer whorl of sepals forms the calyx, and the inner whorl of petals, the corolla. If the perianth is not differentiated into sepals and petals, they are collectively known as tepals. In some
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