Silene marmorensis a terminal cyme of flowers at the top of the stem, and some flowers may occur in the leaf axils. Each flower has a hairy, veined calyx of fused sepals. The flowers bloom at night, the five pinkish or green-tinged petals opening at the tip of the calyx. This species is threatened by logging operations and other degradation of its habitat. Silene marmorensis Silene marmorensis is a rare species of flowering plant in the pink family known by the common names Marble Mountain catchfly, Marble Mountain campion, and Somes Bar campion. It is endemic to the southern Klamath Mountains of
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.