Saturday, July 18, 2009
Snow Buttercup Ranunculus adoneus. Snow buttercups exhibit suntracking or heliotropism.
The stalks of the flower move with the sun carrying the flower heads and this occurs because of
differential cell growth. The stalks bend eastward in the morning and gradually unbend during
the course of the day. Photoreception occurs in the middle region of the stalk 1-3 cm below the
flower. This is due to 40% increased growth on the shaded side of the stalk and corresponds
to significantly longer epidermal cells on that side in contrast to the sunlit side.