Stellaria umbellata inflorescence is an umbel-shaped array of several flowers each on an arching or erect pedicels. The flower has five pointed green sepals each no more than 3 millimeters long. There are occasionally tiny white petals within the calyx of sepals, but these are generally absent. Stellaria umbellata Stellaria umbellata is a species of flowering plant in the pink family known by the common names umbrella starwort and umbellate starwort. It is native to western North America from Alaska and northwestern Canada to the southwestern United States, as well as parts of Asia, including Siberia. It grows in subalpine and alpine
Calyx of Held embryonic calyx formation. One characteristic that distinguishes Eph proteins and their receptors from other signaling systems is their ability to transmit information bidirectionally. Forward and reverse signaling in VCN and MNTB cells is essential for the proper number and formation of VCN and ipsilateral MNTB projections in the calyx. Eph proteins also ensure that while axons pass through the ipsilateral MNTB, branching and final termination of these projections only occur in the contralateral MNTB, possibly because the proteins are only targeted towards specific regions on the axons. Overall, there are two ultrastructural changes that occur in the calyx of Held.