Leon Chua postulated the theory of a memristor - a resistor with memory - in 1971, and the first solid-state memristor was built in 2008. Memristors exist in vivo as components of plasma membranes in plants, fruits, roots and seeds. A memristor is a nonlinear element; its current-voltage characteristic is similar to that of a Lissajous pattern. Here, we found memristors in flowers. Electrostimulation by bipolar periodic sinusoidal or triangular waves of an androecium, a spur, petals and a pedicel in Sunpatiens flowers induces hysteresis loops with a pinched point at low frequencies between 0.1mHz and 1mHz. At high frequencies, the pinched hysteresis loop transforms to a non-pinched hysteresis loop instead of a single line I=U/R for ideal memristors because the amplitude of electrical current depends on capacitance of a flower's tissue and electrodes, frequency and direction of scanning. The discovery of memristors in Sunpatiens (Impatiens spp.) creates a new direction in the modelling and understanding of electrophysiological phenomena in flowers.