Fauchea laciniata is deep red in color with a blue-violet or yellow-green iridescent luster.  The thallus can grow to be anywhere between 3-12 cm tall with thin, leafy, fan shaped blades.  Blades of this species are dichotomously branched (Lamb et al. 2005).  The medulla within the blades are 3-4 cell layers thick (Abbott et al. 1976).  A small, discoid holdfast is present which is used for attachment to rocks or other hard substrate (O’Clair et al. 2000).

Fauchea laciniata is a highly variable species and has a wide variety of sizes, shapes, colors and textures.  Spines may be present on cystocarps of some specimens while others are smooth to the touch.  Colors range from red to iridescent blue-violet to yellow-green.  It has been thought that there is a possible correlation between size and shape of the specimen with depth, substrate and degree of exposure (Smith, 1969). 

Fauchea laciniata f. pygmaea and Fauchea media have been thought to be separate species of Fauchea because of their variation in size.  Given their similar traits with F. laciniata and the fact that their only distinguishable trait is their size differences, these two species are considered to be small versions of F. laciniata (Smith, 1969).  They mature much earlier than F. laciniata, reaching full maturity at ~3cm or less as opposed to ~12cm (Dawson, 1950).  

References:

Abbott, I.A. and G.J. Hollenberg. Marine Algae of California. Stanford California:Standford University Press, 1976.

Dawson, E.Y.. “Notes on Pacific Coast Marine Algae.” American Journal of Botany 37.5 (1950): 339-341.

Lamb, A. and B.P. Hanby. Marine Life of Pacific Northwest: A Photographic Encyclopedia of Invertebrates, Seaweeds and Selected Fishes. British Columbia: Harbour Publishing, 2005.

O’Clair, R.M. and S.C. Lindstrom. North Pacific Seaweeds. Auke Bay, Alaska: Plant Press, 2000.

Smith, G.M.  Marine Algae of the Monterey Peninsula California. 2nd ed. Stanford California: Stanford University Press, 1969.