- Blue markers: specimen records
- Yellow marker: type locality, if present
- Red markers: endpoints of range from literature
Life History: Uninvestigated, but with isomorphic stages Phenology: tetrasporangial and sterile in the northern and southern parts of its range (Hollenberg and Wynne 1970).
Amplisiphonia Hollenberg 1939
Thalli prostrate, dorsiventral, expanded membranes, with rounded overlapping lobes, attached by numerous unicellular rhizoids from lower surface. Growth marginal from continuous row of apical cells, each cutting off derivatives and forming firmly adjoined polysiphonous branches, these branching dichotomously. Component branches with 3 dorsal and 2 ventral pericentral cells, uncorticated. Tetrasporangia obliquely cruciately divided, arising in narrowly attached, marginal, often ruffled lobes. Spermatangial stichidia curved, borne spirally on numerous slender marginal branchlets. Cystocarps numerous, marginal, briefly pedicellate.
Amplisiphonia pacifica Hollenb.
Hollenberg 1939b: 382; Smith 1944: 372; Scagel 1953: 39; Hollenberg & Wynne 1970: 175.
Thalli in tightly adherent patches to 5.5 cm broad, but coalescing and overlapping others to 10-15 cm; lobes 140 µm thick, medium to dull red; tetrasporangial lobes marginal, ample, often ruffled at maturity, to 5 mm long, 6 mm broad; spermatangial stichidia cylindrical, 150-l90(220) µm long, +/- 50 µm diam., narrowed apically, 1 per segment, on marginal radial branches, the stichidia curving inward, often with a few short, sterile apical cells; mature cystocarps ovoid to globular, 400-550 µm diam., 530-700 µm long.
Frequent on rocks, sometimes on other algae, midtidal to subtidal (to 25 m), N. Br. Columbia to Pta. Eugenio, Baja Calif. Type locality: Corona del Mar (Orange Co.), Calif.
Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.
