UC specimens and range limits for Ulva intestinalis

• 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

Status: This species can usually be confidently identified. Confirmed by DNA sequence in British Columbia, Nova Scotia, New Brunswick, Canada (Saunders & Kucera 2010); Bodega Head, Sonoma Co.,Calif.; Botany Bay, Vancouver Island, British Columbia, Canada; Valdez-Cordova Co., Alaska (Hayden & Waaland 2004); to San Diego in California; apparent disjunction between Mussel Shoals, Mendocino Co. and Chetco River, Oregon.

Habitat: Upper intertidal, in freshwater seeps or pools to low intertidal, subtidal; opportunistic settler in disturbed habitats

Life History: Alternation of isomorphic phases, with the sporophyte producing quadriflagellate zoospores and unisexual gametophytes producing biflagellate anisogametes; male and female gametes capable of parthenogenetic development (Tanner 1986; Chihara 1969a; Smith 1947).

Search Sequences in GenBank

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

Ulva Linnaeus 1753

Thalli membranous blades, broadly expanded, distromatic, mostly without hollow margins. Blades annual, mostly without stipe; rhizoidal processes from multinucleate lower cells extending downward between blade margins forming usually perennial holdfast. Cells of blade mostly uninucleate. Chloroplast single, laminate or cup-shaped, usually on outer face of cell, with 1 to several pyrenoids. Sporangial and gametangial thalli usually morphologically similar; fertile areas marginal or terminal; zoospores quadriflagellate. Gametes biflagellate, isogamous or anisogamous. Zygote germinating without dormant period.

"Gomontia polyrhiza," which may be a stage in the life history of species of Ulva, is described on p. 120.

Enteromorpha intestinalis (L.) Link

Ulva intestinalis Linnaeus 1753: 1163. Enteromorpha intestinalis (L.) Link 1820: 5; Doty 1947a: 14; Bliding 1963: 139; Scagel 1966: 49 (incl. synonymy).

Thalli unbranched, 4-20(200) cm long, tubular, cylindrical throughout, or broadening distally, often becoming slightly compressed and expanded above, or occasionally with a few small basal proliferations; cells in surface view irregularly arranged, angular, usually with rounded corners (8)10-18 µm diam.; chloroplast almost filling cell and with 1(2 or 3) pyrenoids; transection 20-55 µm thick, thicker near base; cells near base vertically elongated, (8)12-18 µm wide, 12-30 µm long; protoplast located closer to outer wall in lower portion of thallus.

On rocks, epiphytic on other algae or often free-floating, high to midtidal, in protected areas of bays or estuaries, Kukak Bay, Alaska, to Mexico, and in Chile; common throughout Calif. Type locality: probably N. Europe.

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: As Enteromorpha in MAC. Molecular studies demonstrated that Enteromorpha and Ulva are synonyms; Ulva has priority (Hayden et al. 2003).