- Blue markers: specimen records
- Yellow marker: type locality, if present
- Red markers: endpoints of range from literature
Laurencia Lamouroux 1813
Thalli chiefly erect, solitary or tufted, epiphytic or saxicolous; erect axes cylindrical to markedly flattened; branching pinnate or radial. Branch apices blunt, with terminal pit containing single apical cell and rudimentary, evanescent trichoblasts; branches firm to cartilaginous, solidly parenchymatous, with obscure polysiphonous core surrounded by cortex of usually isodiametric cells, these sometimes with lenticular thickenings in walls. Tetrasporangia tetrahedrally divided, scattered in outermost cortical layers of branchlets. Spermatangial branches cylindrical, densely crowded in conceptaclelike terminal pockets. Procarps arising in apical pits; cystocarps morphologically terminal.
Laurencia pacifica Kyl.
Kylin 1941: 42; Smith 1944: 378; Dawson 19631): 457 (incl. synonymy).
Thalli deep reddish-purple, usually with numerous radially branched, erect axes 6-16(30) cm tall, +/- 2 mm diam. below, arising from primary discoid holdfasts, generally obscured by numerous stolons, forming perennial basal cushion; erect axes of older plants mostly percurrent; branching irregularly alternate, subopposite or subverticillate, of 3 or 4 orders, the ultimate branchlets turbinate, 1-3 mm long, not dense or wartlike; cortex lacking lenticular thickenings; surface cells not forming palisade-like layer, each containing single spherical hyaline body; tetrasporaugia in compound branchlets, these tending to form very dense, verticillate clusters around strongly percurrent upper parts of main axes; spermatangia in branched clusters in apical pits; cystocarps 1-1.2 mm diam., on upper branchlets.
Common to abundant in restricted localities, on rocks, low intertidal, usually in cool quiet water, Monterey Peninsula, Calif., to I. Magdalena, Baja Calif. Type locality: La Jolla, Calif.
The various forms of this highly variable species are treated by Dawson (1963).
Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.
