4 KudoZ points awarded for this answer. Comment: "Thank you both for your answers - I was not sure which to choose. However, in the end, I think that it may be best to be more precise here because the boot stage encompasses different events. The moment when the flag leaf sheath opens appears to correspond to the 'gaine éclatée' - as far I can see. It may be possible to call this the 'pre-boot' stage too - I'm not 100% sure. In any case, I wish I could divide up the points as both answers have been of great help. Thanks again! Sheila"