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 nucleus of the trapezoid body) and VCN (ventral cochlear nerve), eventually connecting with one another by projecting across the midline of the two areas. These associations begin to appear immediately after VCN neurons have been generated; one can observe the earliest formation of these contacts around embryonic day 17 (E17). These neuronal connections, which make up an important area of the cochlea, form branches with one another that terminate in the calyx of Held. Over the course of the next two to three weeks, the neuronal contacts that first formed the embryonic calyx evolve in shape and function, culminating in