Withy

A withy or withe (also willow and osier) is a strong flexible willow stem, typically used in thatching, basketmaking, gardening and for constructing woven wattle hurdles.

[2][3][1] The term is also used to refer to any type of flexible rod of natural wood used in rural crafts such as hazel or ash created through coppicing or pollarding.

The Somerset Levels remain the only area in the UK growing basket willow commercially.

Withies were used to mark minor tidal channels in UK harbours and estuaries.

Note the images of international navigation-chart symbols for withies (port and starboard).