A Vogel spiral is a discrete arrangement of points whose polar coordinates are
 |  |  |
(1)
|
 |  |  |
(2)
|
where 
,
, and 
is a fixed divergence angle
(Vogel 1979). The customary choice 
is the golden
angle and produces the interlacing spiral patterns
used to model phyllotaxis in sunflower heads.
The radii satisfy the equation of Fermat's spiral, but a Vogel spiral is a discrete point set rather than a continuous plane curve.
A daisy similarly produces a flower-like family of visible spirals by placing repeated shapes along a spiral, but it generally uses different radial scaling.
