UC specimens and range limits for Pterosiphonia bipinnata

• 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

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

Pterosiphonia Falkenberg 1897

Thalli chiefly erect from prostrate branches; erect branches alternately distichous, with subordinate branches of 1 to several orders. Branches cylindrical to strongly compressed, with 4-20 pericentral cells, usually uncorticated. Ultimate branchlets determinate, typically without trichoblasts. Tetrasporangia 1 per segment in straight series, mostly in ultimate branchlets, tetrahedrally divided. Spermatangial stichidia clustered near apices of determinate branchlets or on spurlike branchlets from determinate branches, distichously arranged, with or without sterile apices, arising from entire trichoblast primordium. Cystocarps ovoid to globular, briefly pedicellate.

Pterosiphonia bipinnata (Post. & Rupr.) Falk.

Polysiphonia bipinnata Postels & Ruprecht 1840: 22. Pterosiphonia bipinnata (Post. & Rupr.) Falkenberg 1901: 273; Smith 1944: 366. Pterosiphonia robusta Gardner 1927a: 102. Polysiphonia californica var. plumigera Harvey 1862: 168.

Thalli dark brownish-red to bright red, 6-12(25) cm tall; erect branches cylindrical, uncorticated, laxly and repeatedly branched; final orders of branching distichous and sometimes dense, commonly with recurved branchlets near base of different orders of branches; major branches 180-200(260) µm diam., with mostly 3 segments between successive branches; pericentral cells 11-12(18); tetrasporangia in straight series in ultimate and subultimate branches; spermatangial stichidia 3 or 4, sometimes more, on short spur branchlets, these adaxial on lower third of ultimate branches, 400-480 µm long, 80-90 µm diam., with sterile apex of 3 or 4 short cells; cystocarps globular, to 450 µm diam.

Frequent on rocks, midtidal to upper subtidal, most common on exposed coast, Japan and Alaska to San Pedro, Calif. Type locality: Kamchatka Peninsula, U.S.S.R.

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