Spiralling upward

Kalman Schulgasser, Allan Witztum

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Thin vertical leaves often manifest twist. Perhaps the most prominent example of this is in Typha sp., but such twist is also apparent in Narcissus, Pancratium and many other genera. Such a blade is often referred to as a "spiral leaf". We will indicate the mechanical advantage afforded to the leaf by this arrangement, i.e. that it permits the leaf to achieve a greater height without losing stability, that is bending over due to its own weight. We quantify this gain and show how by a simple experiment it can be shown that the advantage is indeed utilized in nature. Typha domingensis is offered as an example.

Original languageEnglish
Pages (from-to)275-280
Number of pages6
JournalJournal of Theoretical Biology
Issue number2
StatePublished - 21 Sep 2004


  • Spiral leaf
  • Stability
  • Typha

ASJC Scopus subject areas

  • Statistics and Probability
  • Modeling and Simulation
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Agricultural and Biological Sciences
  • Applied Mathematics


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