UC specimens and range limits for Dictyota binghamiae

• 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: Of the California Dictyota species, this has the broadest and most northerly distribution, from Haida Gwaii, British Columbia, Canada to locations in Washington, Oregon, California, and Baja California, Mexico. In California, from Mendocino to San Diego counties, including the California Channel Islands, except Santa Rosa Island.

Status: This species has not been compared to others in the genus, though 2 COI sequences from specimens from Bamfield, British Columbia, Canada are in GenBank (McDevit & Saunders 2009).

Habitat: Kelp forests and shallow subtidal

Life History: Presumably alternation of isomorphic phases, with a diploid thallus bearing unilocular aplanosporangia and dioecious haploid thalli bearing either oogonia or antheridia

Search Sequences in GenBank

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

Dictyota Lamouroux 1809

Thalli erect, complanate, without midrib, typically dichotomo-flabellately branched, arising from branched stolons. Branches each with single large apical cell. Medulla of a single layer of large colorless cells. Cortex usually of a single layer of much smaller pigmented cells in longitudinal rows; hairs common on sterile thalli. Dioecious; oogamous; reproductive structures exserted. Sporangia unilocular, scattered over both surfaces of blades, each producing 4 aplanospores; oogonia in sori, each oogonium producing a single relatively large egg. Antheridia plurilocular, in sori with sterile margin.

Dictyota binghamiae J. Ag.

J. Agardh 1894: 72; Dawson 1950d: 268; Hollenberg & Abbott 1966: 19 (incl. synonymy).

Thalli light to medium brown, darker near base, 15-25(35) cm tall, with slight to pronounced tendency to pinnate branching, even in young plants, owing to unequal growth of branches; branches 1-1.5(2) cm broad, with broadly rounded apices and usually with numerous minute marginal teeth; medulla monostromatic throughout; cortex monostromatic except near holdfast, where composed of 3 or 4(6) cell layers; antheridial sori oval, on both surfaces; oogonial sori scattered on both surfaces, round, mostly 140-440 µm diam.; oogonia 80-95 µm diam.

Occasional to locally common, mostly subtidal (6-9(30) m), on rocks, Queen Charlotte Is., Br. Columbia, to C. Baja Calif; in Calif., known chiefly from Monterey region, especially Carmel Submarine Canyon. Type locality: Santa Barbara, 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: Also very common in the California Channel Islands.