The bank is a pragmatic response. It acts as a genetic insurance policy. Finding and harvesting all these seeds is not as easy as it might seem. Still others may bloom during a narrow period of time. And those are just the ones you can see.
Microscopic seeds present a whole new set of problems.
On this winter afternoon, FitzGerald is tromping through the mud in a patch of the New Forest called Standing Hat. As predicted, few of the scraggly bushes have berries. Every now and then she bends down to collect one or two. But after an hour her cloth bag has only about a dozen, which will yield roughly 36 seeds. In the early going of the collecting phase, the seed bank asked for thousands of seeds from each species.