Figure 1. Passive hydraulic actuation of the coalified cones and, for comparison, of a cone scale of extant P. sylvestris.

(a) Cones and scales of Keteleeria spec. from the Middle Miocene and (b) of Pinus spec. 1 from the Eemian Interglacial. (c) Hydration of the whole Pinus spec. 2 cone from the Middle Miocene, the timescale after wetting is indicated. At t = 9,5 min, the swelling process is completed and the seed scales are notably bent upwards. Frames are from Supplementary Video S1. (d) Hydration and angular change over time of coalified, separated seed scales (red: Keteleeria sp., blue: Pinus sp. 1, grey: P. sylvestris).