Fig. 4. Echo fingerprints of flowers in Markea neurantha. (A) Sketch of the flower (scale bar, 20 mm). (B) Duration of the impulse response for 90 directions in the horizontal plane (-90° to +90° in 2° increments). (C) The directional pattern of the impulse response (black, positive amplitudes; white, negative amplitudes; see Fig. 2). (D) Overall amplitude of the echo. (E) Spectral directional pattern from 20 kHz to 140 kHz (black, 0 dB to -6 dB; grey tone gradation in steps of 6 dB corresponding to the scale given in Fig. 2).