Whilst tramping through the reed on Guist Common, we came across a couple of willow shrubs.  The subopposite smallish (9-12mm), slightly curved, male flower buds with a slight reddish tinge suggested Purple Willow.  To confirm the identity we stripped the bark off a young twig to find the yellowish inner surface.  

The single bud scale can be seen dropping off an expanding bud, the anthers are still hidden amongst the densely hairy catkin scales and the 2-3 leaf-like bracts are just visible at the base of the catkin.