As phallus elongates, it pulls forward urethral folds that surrounds urogenital sinus together. The rachis elongates after each conidium is produced, resulting in a long zig-zag extension. Lichen undergoes diffuse growth and the thallus elongates over time. The C-C bond elongates and weakens causing fragmentation. If exposed to testosterone, the genital tubercle elongates to form the penis. Once healed, the procedure effectively elongates the frenulum, allowing normal function. Likewise the pineal stalk of "Petromyzon" elongates very considerably during metamorphosis. During germination, the tube cell elongates into a pollen tube. The solar wind elongates these loops to pointy tips. The hypocotyl elongates while the epicotyl remains the same in length. In some frogs, the tongue elongates up to 180% of its resting length. It is very flexible and elongates under stress. In stage I, the sporangiophore initially elongates at the apex, but does not rotate. Each preameloblast elongates and becomes an postmitotic, polarized, secretory ameloblast. When the inhibition is alleviated late at night, the hypocotyl elongates.