Previous taxon California Seaweeds eFlora Index to accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M |
| N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Next taxon

Stephanocystis setchellii

(N.L. Gardner) S. Draisma, E. Ballesteros, F. Rousseau, & T. Thibaut

Key Characteristics

  • Stipe triangular in cross-section, with flattened blades with midrib 1-2 divided into pinnae
  • Upper portions short, flat, pyramidal, with large, spherical floats in series of 1-5

Image Gallery (click for more)

Database links

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).

Classification: Algaebase


Vertical Distribution: Subtidal, kelp forest habitats

Frequency: Infrequent

Substrate: Rock

Type locality: San Pedro and Redondo, Los Angeles Co., California

Specimen Gallery (click for more)

Copyright © 2023 Regents of the University of California
Citation for this page: Stephanocystis setchellii, in Kathy Ann Miller (ed.), 2023 California Seaweeds eFlora, [accessed on June 09, 2023]
Citation for the whole website: Kathy Ann Miller (ed.) 2023. California Seaweeds eFlora, [accessed on June 09, 2023].

We encourage links to these pages, but the content may not be downloaded for reposting, repackaging, redistributing, or sale in any form, without written permission from The University Herbarium.