Iodine is a chemical element with symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a lustrous, purple-black metallic solid at a standard conditions that sublimes readily to form a violet gas. The elemental form was discovered by the French chemist Bernard Courtois in 1811.
Definition of CHOLLA. : any of numerous shrubby opuntias chiefly of the southwestern United States and Mexico that have needlelike spines partly enclosed in a papery sheath and cylindrical joints âcalled also cholla cactus.
Healthy Christmas cactus foliage is bright, glossy green. The Christmas cactus (Schlumbergera bridgesii) earned its common name with the timing of its bloom, which occurs at Christmas if the plant has been given 8 weeks of long nights -- 13 hours or more of dark - for eight weeks preceding Christmas.