UC specimens and range limits for Laminaria 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: Broad distribution from Alaska south to San Miguel, Santa Rosa, Santa Cruz, and San Nicolas islands in southern California. There is a disjunction between these island populations and upwelling areas in the northern portion of Baja California, Mexico, where this species has been reported (Pedroche et al. 2008).

Status: This species is easy to identify, except when young (<10 cm tall), when many species in the Laminariales look very similar. It was called Laminaria dentigera in MAC, but this species occurs in the Arctic and not in California.

Habitat: Growing in the low intertidal zone on rock; often hanging off walls. The drooping blade, or its remnants, can be seen extending above the waterline at very low tides. In Canadian populations, individuals growing in more exposed sites are taller, with thicker stipes, than those in more protected sites.

Life History: Alternation of heteromorphic phases (large diploid sporophyte and microscopic haploid dioecious gametophytes). Blades are deciduous, eroding away during summer, when growth stops, and renewing growth during the short days of winter. A constriction between the old and new blade is often evident. Annual growth rings can be seen in cross sections of the stipe near the holdfast; plants may live up to 20 years (Klinger & DeWreede 1988). Reproduction is also induced by short day lengths; spores are produced in irregular dark sori on the blade. Gametophytes can survive for >18 months in total darkness (tom Dieck 1989).

Associated Taxa: Pterygophora californica, at some sites; Pyropia gardneri, small filamentous brown algae

Search Sequences in GenBank

Illustration from DeCew's Guide to the Seaweeds of British Columbia, Washington, Oregon, and Northern California

Laminaria dentigera Kjellm.

Kjellman 1889a: 45; Setchell & Gardner 1925: 604; Druehl 1968: 546. Hafgygia andersonii Areschoug 1883: 3. Laminaria andersonii sensu Smith 1944: 137. L. cordata Dawson 195021: 153. L. setchellii Silva 1957b: 42.

Sporangial plants perennial from stipe, to 1.5(3) m long, with single stipe produced from each holdfast; holdfast of stiff, branched haptera compacted into conical mass 6-8 cm tall in older plants; stipe to 3 cm diam. near base, tapering and becoming slightly complanate to markedly flattened near blade; older stipes with concentric rings in outer cortex and mucilage ducts internal to innermost ring as seen from base of plant; mucilage ducts in upper stipe nearer surface and concentric rings lacking, the ducts entirely lacking in some specimens; blade ovate and entire in juvenile plants; blade smooth, 14-24 cm wide, in mature plants, appearing palmate by virtue of deeply incised linear divisions more or less equal in width, rarely to 1 m long; mucilage ducts present (except as noted above); sori appearing in late fall as irregularly linear dark patches; regeneration of new blades often beginning before old blades are shed. Common in groups, saxicolous, lower intertidal to upper subtidal of moderately exposed areas, Bering Strait to Ensenada, Baja Calif. Type locality: Bering I. (Komandorski Is.), U.S.S.R.

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: Silva (1957) explained the misapplication of the name Laminaria andersonii Eaton ex Hervey (as in Smith 1944) and proposed L. setchellii as the correct name for this species. Nicholson (in Abbott & Hollenberg 1976) merged L. setchellii with L. dentigera Kjellman, although Druehl (1968), in his monograph of the genus, had stated that the two species were easily distinguishable.

The correct name is Laminaria setchellii P.C. Silva 1957, a new name that replaces Farlow's Laminaria andersonii 1891, a name that is illegitimate because it is a later homonym (i.e., the name has been used previously) of Laminaria andersonii Eaton ex Hervey 1881. This latter name refers, in error, to Laminaria sinclairii. The type locality of Laminaria setchellii is Santa Cruz, California.