Sargassum muticum (Yendo) Fensholt
Annotated by Robert F. Scagel.

Washington: San Juan County: Argyle Lagoon, San Juan Island
48° 31' N, 123° 1' W
Datum: WGS 84. Uncertainty: 301 meters. Coordinate Source: Digital Map.
On rocks, shells and old wood in the upper subtidal zone. Description: Thallus erect, 1-3 m, attached by a small conical discoid holdfast. The basal part comprises a short stalk from which arise numerous branches. Near the base leaf-like branches arise from the main axes which are broad, somewhat dentate and possess a faint midrib. The distal portions of the main axes give rise to shorter, narrower leaf-like branches and numerous small air vesicles and swollen receptacles. The vesicles are produced singly and are quite smooth. Colour yellowish brown to tan. Substrate: rock, shells, wood.

Robert F. Scagel 53, Aug 5, 1955
OSC, Barcode: OSC-A-011211, 25