 The naturally occurring plant form of alpha-tocopherol (vitamin E) is RRR-α-tocopherol whereas the synthetic form (all-racemic vitamin E, or dl-tocopherol) is equal parts of the stereoisomers RRR, RRS, RSS, SSS, RSR, SRS, SRR and SSR with progressively decreasing biological equivalency, so that 1.36 mg of dl-tocopherol is considered equivalent to 1.0 mg of d-tocopherol.Macroscopic examples of chirality are found in the plant kingdom, the animal kingdom and all other groups of organism.A simple example is the coiling direction of any climber plant, which can grow to form either a left- or right-handed helix.