UC specimens and range limits for Silvetia compressa subsp. deliquescens

• 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: On San Nicolas, Santa Cruz, Anacapa, Santa Barbara, Santa Catalina, and San Clemente islands as well as on Islas Los Coronados and at Punta Descanso and Bahia de Todos Santos in northern Baja California, but it is not known from mainland southern California.

Status: Silva et al. (2004) described insular populations of this species in southern California (California Channel Islands) and Baja California, Mexico on the basis of morphological and genetic (ITS sequence) characters. This subspecies is slender, with regular dichotomies, forming a compact dome-shaped canopy; receptacles are oval and blunt -- all characters that contrast with subsp. compressa. "Pelvetia fastigiata f. gracilis" populations in Monterey belonged to subsp. compressa, rather than subsp. deliquescens.

Habitat: Upper intertidal, below Hesperophycus californicus, often forming a distinct band

Life History: Diplontic, with gametic meiosis; monoecious

Search Sequences in GenBank

Pelvetia Decaisne & Thuret 1845

Thalli perennial. Holdfast conical, tough and resilient, producing 1 to several erect, dichotomously branched axes. Axes subcylindrical to compressed and channeled on 1 side, without midrib, with or without gasfilled vesicles. Cryptostomata inconspicuous. Gametangia unilocular and developed within conceptacles at apices of final dichotomies. Oogonium producing 2 (rarely 3-5) large, nonflagellate eggs, the division either longitudinal or transverse. Antheridia producing 128 small, biflagellate sperm. Plants monoecious.

Pelvetia fastigiata f. gracilis S. & G.

Setchell & Gardner 1917a: 386; Smith 1944: 154.

Thalli slender as compared to those of f. fastigiata, and more profusely branched, with receptacles 0.5-1 cm long; resembling Pelvetiopsis arborescens.

Locally abundant, on rocks, Pebble Beach (type locality) and Channel Is., Calif., where it is abundant and replaces P. fastigiata f. fastigiata in narrow band below Hesperophycus harveyanus.

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 Pebble Beach population is now considered to be S.compressa subsp. compressa.