Nettles that don't sting

The leaves look like stinging nettles but this white flower shows it is the white dead-nettle.  (Stinging nettle flowers are like green catkins.)  The name "dead" nettle tells you that it is not a stinger.

Bumble bees visit the white dead-nettle flower to collect the sweet nectar at the bottom of each flower's tube.  What they don't realise is that when they alight on the lower lip of each flower like a landing platform, the stamens in the hooded upper lip dust their furry backs with pollen.  The bees then carry the pollen to the next flower and so fertilise it.