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Spirals on the Sunflower

Parastichy, in phyllotaxy, is the (invisible) spiral line of the pattern of the areoles on some plants, such as cactuses and pinecones.[1] These spirals involve the insertion of a single primordium.[2] They have been described as an effect of the human eye and the way it connects "nearest points" on certain spiral patterns.[3]

See also[edit]


  1. ^ Webster's Revised Unabridged Dictionary. C. & G. Merriam Co. 1913. 
  2. ^ Weise, Dmitriy (1998-10-29). "Principle of Minimax and Rise Phyllotaxis". Retrieved 2008-12-14. 
  3. ^ Spiral Lattices, Smith College

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