Evolution of its own parasite:

Fauchea laciniata is commonly found as the host of the parasite Faucheocolax attenuata.  Faucheocolax attenuata is an adelphoparasite which is defined as a parasitic red algae that is morphologically very similar to its host (Goff et al. 1996).  Given the fact that there are strong similarities between Faucheocolax and its host F. laciniata, it is believed to have evolved directly from its host or from a similar species, F. fryeana.  This evolution is apparent because many adelphoparasites are more closely related to their hosts than they are to other parasites of the same genus (Goff et al. 1996).

How do hosts create their own parasites?

Parasites that are strongly related to their host species are able to establish secondary pit connections with the host much easier and have easy access to nutrients.  These pit connections between vegetative cells also allow for the transfer of nuclei between the parasite and its host.  Red algae have adapted the ability to transfer genomes between the host cells, this adaptation gives them the ability to transfer host cells into the parasite cells via the pit connections.  The parasitic nuclei may be replicated within the host cell and then passed on to other host cells.  Once a host cell contains the nucleus of the parasite it becomes a parasitic cell which can then release spores and gametes to reproduce and spread (Goff et al. 1996).

Another possible mechanism for a parasite evolving from its host is by a parasitic genome entering the host and altering its developmental programs to replicate and disperse the parasite (Goff et al. 1996).

In the case of Fauchea laciniata and Faucheocolax attenuata, studies have been done comparing their ITS sequences.  By doing this it is shown that Faucheocolax did in fact evolve either directly from F. laciniata or evolved from F. fryeana and transferred to F. laciniata.  The exact evolutionary host cannot be determined because the sequences are too similar (Goff et al. 1996).

Faucheocolax attenuata:
Tiny red parasitic algae whose thalli is parasitic on Fauchea.  Can be whitish to pinkish in color (Lamb et al. 2005).  It has a tiny thallus with a solid basal cushion containing many wart-like branches used for reproduction.  Similar to Fauchea, it has cystocarps and tetrasporangia as its reproductive structures (Dawson, 1950). 

Iridescence:

Fauchea laciniata is recognized by its beautiful iridescence which varies among individuals and can be blue-violet or yellow-green in color.  This iridescent sheen is caused by gland cells located within the surface layer of the epidermis (Lamb et al. 2005).  Light is reflected and refracted off of this multi layered cuticle to form a variety of brilliant colors (Mondragon et al. 2003).  This phenomenon is called “thin layer interference” (Vidargas, 2003). 

For more information on the process and visuals visit: http://www.mbari.org/staff/conn/botany/reds/FaucheaWebsite/iridescence.htm

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.

Goff, L.J., D.A. Moon, P. Nyvall, B. Stache, K. Mangin, and G. Zuccarello. “The Evolution
of Parasitism in the Red Algae: Molecular Comparisons of Adelphoparasites and their
Hosts.” Journal of Phycology 32 (1996): 297-312.

Guiry, M.D. and Guiry, G.M. AlgaeBase. 2008. World-wide electronic publication, National
University of Ireland, Galway. 01 May 2008 <http://www.algaebase.org.>

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.

Mondragon, J. and J. Mondragon. Seaweeds of the Pacific Coast: Common Marine Algae
 from Alaska to Baja California. Monterey, California: Sea Challengers Publication, 2003.

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.

Vidargas, N. Monterey Bay Aquarium Research Institute. 2003. 2 May 2008.
 <http://www.mbari.org/staff/conn/botany/reds/FaucheaWebsite/index.htm.>

Vijayaraghavan, M.R. and B. Bhatia. Red Algae: Structure, Ultrastructure and
            Reproduction. Darya Ganj, New Delhi: Aph Publishing Corporation, 1997.