UC specimens and range limits for Agarum fimbriatum

• 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 southeast Alaska (57.033333, -135.35; UBCA90237) to Isla Todos Santos, Baja California, Mexico (31.8096031,-116.80563; UBCA70043), but with a large disjunction between Washington and the Southern California Bight.

Status: This species is not closely related to others in the genus Agarum. Recent studies (H. Kawai, pers. comm.) place it in a new genus, Neoagarum.

Habitat: Growing on rocks in the low intertidal to subtidal in the north; in southern California, part of the deep water seaweed assemblage (20-35m).

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

Associated Taxa: In southern California, Laminaria farlowii, Pelagophycus porra

Search Sequences in GenBank

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

Agarum Bory 1826

Sporangial thalli with holdfast composed of small, branched haptera. Unbranched stipe short, cylindrical or flattened, at times fimbriated, supporting single blade. Blade relatively thin, 0.5-1 mm thick in mature specimens, with narrow to broad percurrent midrib and perforated lateral wings (sometimes also bullate and undulate). Sori forming broad patches on both surfaces of blade.

Agarum fimbriatum Harv.

Harvey 1862: 166; Setchell & Gardner 1925: 616.

Thalli with haptera profuse and slender in specimens growing on wood in sheltered locations, larger and denser in old plants growing in exposed areas; stipe usually flattened, 2-6 cm long, 4-7 mm wide, with numerous, often branched fimbriae on margins, particularly near blade; blade thin and bullate, nearly circular to narrowly elliptic in outline, 20-80 cm long, 15-26 cm wide, the base rounded or slightly cordate, the margin crisp and fimbriate, the midrib fairly broad, complanate; perforations few and irregular in outline; sori borne on blades as irregular dark patches.

Frequent on rocks, wood, or other algae: midtidal or subtidal from Alaska through Puget Sound; subtidal (to at least 115 m) in Calif. only south of Point Conception and around Channel Islands. Type locality: Esquimalt, British Columbia.

Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.