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Stephanocystis neglecta

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

Key Characteristics

  • Stipes triangular in cross-section
  • Blades flattened and dissected 2-4 times into sharp sections
  • Upper portions open, loose and thread-like; floats solitary or 1-3 mm apart in series

Image Gallery (click for more)

Database links

UC specimens and range limits for Stephanocystis neglecta
  • 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, common at Santa Catalina and San Clemente islands and Baja California, Mexico; also at Santa Cruz, Santa Barbara and Anacapa islands and from Los Angeles through San Diego cos. on the mainland. Old specimens from Monterey and Santa Barabara are probably from the drift.

Status: Specimens from Santa Catalina Island and Point Loma, San Diego Co. were 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, including Halidrys dioica, 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

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 neglecta S. & G.

Setchell & Gardner 1917b: 388.

Thalli to 1(1.5) m tall, medium brown in life; lower thallus (2)3 or 4 times pinnately divided, the ultimate divisions very slender or with acute, trailing apices; upper thallus intricately branched, divaricate; pneumatocysts developing on separate filiform branches, solitary, or in series but 1-3 mm apart, spherical, smooth, 2-3 mm diam.; plant dioecious; receptacles sparingly branched, terminal on upper branches, nearly filiform, with conceptacles strung along length and producing beaded appearance.

Infrequent, saxicolous, shallow subtidal, Santa Catalina and San Clemente Is., Calif. Type locality: Avalon (Santa Catalina I.), 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: Now Stephanocystis; Cystoseira is a European genus (Harvey & Goff 2006; Draisma et al. 2010). See Distribution for update.

Classification: Algaebase


Vertical Distribution: Shallow subtidal

Frequency: Occasional

Substrate: Rock

Type locality: Avalon, Santa Catalina Island, Los Angeles Co., California

Specimen Gallery (click for more)

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Citation for this page: Stephanocystis neglecta, 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].

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