Mystery object

No, not the woodlouse - I imagine most people can recognise that - but the lumpy stuff it's scurrying across, disturbed by my attention. Do you know what it is? It's not uncommon, at least where I live, but it doesn't feature among the familiar signs of spring.

The knot of scaly brown knobs is actually a cluster of fern fronds waiting to unfurl. As the temperature rises these tightly clenched nodules will relax and unroll to release their tender, feathery plumes. It's another of the myriad of magic tricks that the nature plays, year on year.

To my great surprise I could not find a single image of this stage in the annual cycle of male fern when I looked for one on the internet.