I haven't seen this type of seaweed before so would be great to learn about a new one :)
The usual that I see around here with the non smooth leaves.
Quite a few of these ones washed up as well as the some of the smooth ones. Also the part where the leaves branch off is spotted, which the smooth ones don't have.
http://naturewatch.org.nz/observations/2745411 for the smooth ones.
I think this may be Ecklonia radiata but this one is smooth so not too sure if that means that it is old or another species / sub species lurking around here which wouldn't surprise me! *LOL*
Quite a few of these smooth ones washed up as well as the usual rough ones. Also the part where the leaves branch off is not spotted, which the non smooth ones are.
http://naturewatch.org.nz/observations/2745420 for the usual rough leaf ones.
Washed up on beach
Please confirm ID
Growing in a tidal gut