UC specimens and range limits for Desmarestia dudresnayi subsp. tabacoides

• 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: From Cordell Banks, Marin Co., Monterey and Carmel bays, Montana de Oro State Park, San Luis Obispo Co., to La Jolla, San Diego Co., including San Miguel, Santa Cruz, Santa Barbara, San Nicolas islands.

Status: A specimen from Montana de Oro State Park, San Luis Obispo Co., has been analyzed with SSU, ITS (nuclear), cox1 (mitochondrial), and psaA, rbcL (plastid) markers (Yang et al. 2014). This species also occurs in Korea and Japan, and is currently considered a subspecies of the European D. dudresnayi. It may be conspecific with D. dudresnayi subsp. foliacea, a broad-bladed species from Washington and British Columbia; it differs genetically from a Korean specimen (Yang et al. 2014).

Habitat: Subtidal, often deep

Life History: An alternation of heteromorphic generations, with large foliose sporophytes and minute filamentous monoecious gametophytes

Search Sequences in GenBank

Desmarestia Lamouroux 1813

Sporangial thalli perennial, elongate, remarkable in the field owing to large amounts of acids produced when plants are collected, bleaching nearby plants and producing an acrid odor. Holdfast stout, disklike, producing single erect axis, this soon forming opposite or alternate branchlets according to species, rarely unbranched. Axes and branches slightly to markedly compressed; some species remaining finely branched throughout, others becoming foliose. In Calif., a seasonal occurrence of hairs at margins of branches. Thalli containing unangia rarely collected in Calif.

Despite large size of some species (to 3 m long), internal structural features and cell modifications not as elaborate as in order Laminariales. Center of thallus with several axial strands having thick walls and surrounded by thick cortex of colorless cells, interspersed by colorless rhizoids. Surface layer of cells containing many lenticular chloroplasts, without pyrenoids. Tufts of hairs in which the intercalary meristem is found are terminal on branches. In older thalli, some transverse and longitudinal walls frequently pitted; cytoplasmic threads traversing the pits probable. Desmarestia ligulata var. firma (C. Ag.) J. Ag.

Sporochnus herbaceus var. firma C. Agardh 1824: 261. Desmarestia ligulata var. firma (C. Ag.) J. Agardh 1848: 169; A. Chapman 1972: 2 (incl. synonymy). D. foliacea Pease 1920: 322. D. tabacoides sensu Hollenberg 8: Abbott 1966: 20.

Thalli leaflike, with 1 or more blades arising from short stipe and expanding into broad oval to subcordate blades, to 34 cm tall, 21 cm broad, mostly broad-oval; blades occasionally irregularly lobed or with the lateral margin torn; midrib clearly marked throughout length of blade, with 7-20 pairs of opposite veins.

Infrequent, saxicolous, subtidal (3 to 40 m), Br. Columbia, Wash., and Monterey Peninsula, Carmel Submarine Canyon, Granite Canyon (Monterey Co.), and La Jolla, Calif. Type locality: Atlantic Coast of France.

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: Desmarestia dudresnayi subsp. firma occurs in South Africa (Yang et al. 2014).