Structure:

The structure of the plant is uncorticated, uniseriate filaments with repeated in opposite or whorled branches (1st image). With regards to cell structure the refractive colorless gland cells (3rd image down) are often present (Taylor 1945), like-wise pit-plugs are present but only viewable when cells have become hypotonic. (see image to the lower left for details)  The plant maybe 4-8 centimeters in height with holdfast as a filamentous structure if visible.

The cells are uni-nucleate. The overall pattern of the branches is that of narrowing growth at the base of the stipe.  Cells tend to be 15-20μm thick while branch base cells tend to be 125-175μm thick (Kylin 1925). (see second image on the left for details on cell shape and relative size)

References:

Taylor, William R. Pacific Marine Algae of the Allan Hancock Expeditions to the Galapagos Islands, Allan Hancock Pacific Expeditions Vol. 12, University of Southern California Press: Los Angeles, California, U.S.A., 1945.

Kylin, Harald. The Marine Red Algae In The Vicinity Of The Biological Station At Friday Harbor, Wash. Lund: Hakan Ohlsson, 1925.