UC specimens and range limits for Stephanocystis setchellii

• 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

Notes: A southern species, from Santa Barbara to San Diego, including all eight California Channel Islands.

Status: A specimen from Anacapa Island was analyzed with ITS, LSU and rbcL as part of an inquiry into species boundaries of Cystoseira (now Stephanocystis), focusing on the North Pacific (Harvey & Goff 2006). There were two clades in the genus, Pacific and Atlantic; species in the the Pacific clade were transferred to Stephanocystis, leaving the Atlantic species in Cystoseira, a polyphyletic genus.

Habitat: Shallow subtidal, kelp forest understory

Life History: Diplontic, with gametic meiosis; dioecious

Search Sequences in GenBank

Cystoseira C. Agardh 1820

Thalli perennial, differentiated into holdfast, stipe, and branches. Lower thallus persisting (in protected areas) and renewing upper thallus, this of distinctly different morphology. Stipe erect, woody, angled where lateral branches have dropped away, triangular in cross section. Branches radially arranged; lower branches flattened throughout and with slight midrib; upper branches with occasional flattened regions but mainly cylindrical, bearing small pneumatocysts along length, either singly or in catenate series. Gametangia unilocular, developed within conceptacles on receptacles at apices of ultimate branchlets. Plants monoecious or dioecious. Oogonium containing 1 uninucleate egg and 7 residual nuclei, these expelled from cytoplasm before oogonial discharge. Oogonia in C. osmundacea produced successively. Antheridium containing 64 biflagellate sperm.

Cystoseira setchellii Gardn.

Gardner 1913: 329.

Thallus appearing bushy, rarely to 1 m tall, medium brown; lower stipe usually bipinnate, the apices of pinnae acute or bluntly rounded; upper stipe to 50 cm long; pneumatocysts in 2-5 series, occasionally solitary, concentrated toward main axis of terminal portion of stipe, spherical to ellipsoid; receptacles terminal on branchlets, slightly tumid, sparingly to densely branched; plant dioecious.

Infrequent, on rocks near or covered by coarse sand, subtidal (to about 10 m) in areas of relatively calm water, Shell Beach (San Luis Obispo Co.) and Redondo Beach to San Diego, Calif.; abundant at Little Harbor and Pin Rock (Santa Catalina I.), Calif. Type locality: San Pedro, Calif.

No plants from the San Pedro region were found either subtidally or cast ashore during the years 1969-72, and it is probable that this species no longer grows at the type locality. Gardner's discussion (p. 330) indicates that the material he studied was frequently found cast ashore.

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: Now Stephanocystis; Cystoseira is a European genus (Harvey & Goff 2006; Draisma et al. 2010).