quadrivalvis

Updated: May 4, 2025

Its whorls are changed on the twisted parts into clearly visible spirals. The ironwood or Casuarina quadrivalvis is sometimes observed to produce the same anomaly on its smaller lateral branches. Coming now to the discussion of the way in which the twisting is the result of the spiral disposition of the leaves, we may consider this arrangement on stems in the adult state.

Hugo de Vries - Species and Varieties, Their Origin by Mutation