UC specimens and range limits for Alaria marginata

• 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: The southern range limit is in San Luis Obispo Co., at Diablo Cove. The specimen (WTU-A-001593, see specimen gallery) from Smuggler's Cove, Santa Cruz Island, collected at 80-100' depth, may have been a drift specimen, since this species has never been reported from the Channel Islands.

Status: On the basis of molecular sequences (coxI-5', ITS, and rbcL), Lane et al. (2007) merged A. nana, A. taeniata, and A. tenuifolia with A. marginata. California specimens of A. marginata were not included in the study.

Habitat: Low mid- to low intertidal, exposed to wave action

Life History: Alternation of heteromorphic phases (large diploid sporophyte and microscopic haploid dioecious gametophytes).

Search Sequences in GenBank

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

Alaria Greville 1830

Sporangial plants perennial, with single unbranched stipe attached by mass of widely spreading, branched haptera. Stipe short, cylindrical or flattened, terminating in single blade. Blade broadly expanded, undivided, with conspicuous percurrent midrib; surface of blade smooth or bearing cryptostomata. Sporangia produced on linear to obovate flattened sporophylls, these borne on opposite sides of upper end of stipe. Sporophylls usually with each flattened face nearly covered with single large sorus.

Alaria marginata Post. & Rupr.

Postels & Ruprecht 1840: 11; Setchell & Gardner 1925: 640; Smith 1944: 147 (incl. synonymy). Alaria curtipes Saunders 1901b: 561.

Mature sporangial thalli usually 2.5-4(6) m tall, dark tan; stipe terete, 2-7 cm long; blades linear-lanceolate, the length 10-15 times breadth, the broadest (15-30 cm) about one-third distance from base to apex, tapering gradually or somewhat abruptly below broadest portion; all except lowermost portion of blade with cryptostomata; midrib conspicuous, varying considerably in breadth; sporophylls 20-40, sublinear to broadly elliptical, stipitate, with broadly rounded apices, 10-25 cm long, 2-6 cm broad. Locally abundant on exposed rocks, Alaska to Carmel Highlands (Monterey Co.), Calif. Type locality: Unalaska, Alaska. Forms approaching Alaria nana (not recognized in Calif. by Widdowson (1971) may often be found in areas with exceptional exposure to surf.

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: The southern limit is noted here as Carmel Highlands, although several specimens from San Luis Obispo Co. were collected prior to the publication of Abbott & Hollenberg (e.g., UC925033, UC974450). Alaria nana is considered a synonym of A. marginata.