bract

The male flowers grow in catkins, each arising from a scaly bract, and have a green perianth.

This bract, when dead, is bent near the middle and more or less twisted, with the edges curving toward the cluster of nuts.

This bract has attracted a good deal of attention, and for a long time everybody wondered what could be its use.

The little fruit is hung from a broad, flying bract, and as it very slowly sinks to the ground it solemnly turns round and round.

That is because the pressure of the air acts on the flat bract just as it does on an aeroplane, and forces it to revolve.