UC specimens and range limits for Fredericqia chiton

• Blue markers: specimen records
• Yellow marker: type locality, if present
• Red markers: endpoints of range from literature

View map from the Consortium of Pacific Northwest Herbaria

Life History: Gametophytes are monoecious (Doubt, 1935). Following fertilization, gonimoblast filaments are produced from the auxiliary cell and grow through the gametophytic medulla, penetrating the cortex and forming outgrowths that bear tetrasporangial nemathecia (Doubt, 1935). This structure is called a carpotetrasporophyte or tetrasporoblast. Immunochemical evidence suggested that meiosis took place during tetrasporogenesis (McCandless & Vollmer, 1984). Observations of haploid chromosome numbers (n = c. 31) in germinating tetraspores from British Columbia confirmed that meiosis had occurred (Maggs et al. 2013). Spores released from the tetrasporoblast in culture developed into basal discs gave rise directly to erect axes.

Search Sequences in GenBank

Gymnogongrus platyphyllus Gardn.

Gardner 1927a: 247; Doubt 1935: 299; Smith 1944: 274.

Thalli with relatively few erect branches arising from discoid holdfasts; branches 8-15(25) cm tall, dull red to purplish-red, very briefly cylindrical below, with arching parallel fans of branches, these of 3-5 successive, overlapping, flattened dichotomies at wide angles; upper branches uniformly (3)4-6 mm wide, mostly less than 1 mm thick, the apices mostly blunt; spermatangia and free-living tetrasporophytes unknown; "tetrasporoblast" nemathecia (reduced "parasitic" tetrasporophytes) abundant, prominently protuberant, 2-3 mm diam., produced on all but final dichotomies.

Occasional on rock faces, low intertidal to subtidal (to 18 m), S. Br. Columbia to Pta. Santa Rosalia, Baja Calif. Type locality: Duxbury Beef (Marin Co.), Calif.

Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.

Notes: Unpublished culture work by T.C. DeCew, J.W. West and M. Masuda suggested that what was called A. gigartinoides in central and northern California is not that species, which has as its type locality Puerto Angel, Oaxaca, Mexico (tropical Pacific coast). The cool-temperate species has been named Fredericqia decewii C.A. Maggs, L. Le Gall, F. Mineur, J. Provan & G.W. Saunders (Maggs et al. 2013) in honor of DeCew.