- Blue markers: specimen records
- Yellow marker: type locality, if present
- Red markers: endpoints of range from literature
Illustration from DeCew's Guide to the Seaweeds of British Columbia, Washington, Oregon, and Northern California
Rhodoptilum (J. Agardh) Kylin 1956
Thalli erect, irregularly branched, with strongly compressed main axes; branches bilaterally arranged, short, or some as well developed as main axes; cells radially organized, with 5 pericentral cells heavily corticated by rhizoids; branches flattened, densely clothed on margins with monosiphonous, branched, dark bluish-red filaments. Tetrasporangia, spermatangia, and gonimoblasts as in Dasya.
Rhodoptilum plumosum (Harv. & Bail.) Kyl.
Dasya plumosa Harvey & Bailey 1851: 371. Rhodoptilum plumosum (Harv. & Bail.) Kylin 1956: 461. Dasyopsis plumosa (Harv. & Bail.) Schmitz 1893: 231; Okamura 1907-42 (1910): 95. Dasyopsis densa Smith 1943: 217. R. densum (Smith) Dawson 1961b: 448; Daws. 1963b: 402.
Thalli 10-20(40) cm tall, usually with 1 to several leading axes, these strongly percurrent, flattened, to 4 mm broad; branching distichous; primary laterals usually shorter than but occasionally as long as main axes; branching usually of 3 orders, occasionally 4; ultimate orders fringed along margins with branched filaments; northern plants with filaments to 1.5 mm long and forming silky fringe of approximately same length along a given axis, the southern plants with monosiphonous filaments less than 1 mm long, tending to be more tufted or interrupted in distribution along axis; filaments on young thalli and on those from N. Calif. and Wash. continuously distributed; tetrasporangial plants most commonly found.
Locally abundant, saxicolous, subtidal (to 30 m), Queen Charlotte Sd., Br. Columbia, to San Quintin Bay, Baja Calif.; in Calif., from Pt. Arena to La Jolla. Also reported from Japan. Type locality: Puget Sd., Wash.
Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.
