Large Wire Weed (Callophycus)
Pick from shallow, surf-washed rock or washed up on shore.
Sun-dry once removed from saltwater. Then bleach it by wetting and drying it several times until the color is removed. Keep refrigerated, frozen or sun-dried.
J.M. Huisman (via florabase.dec.wa.gov.au)
Large wire weed has stiff and rubbery branches that aredark red in color (Novaczek, 2001).