- Blue markers: specimen records
- Yellow marker: type locality, if present
- Red markers: endpoints of range from literature
Centroceras Kützing 1841
Thalli small, purplish, erect or prostrate, with cylindrical, wholly corticated branches. Branching dichotomous, or irregular; apices forcipate. Cortical cells rectangular and arranged in longitudinal rows, cut off from upper end of large, cylindrical axial cells comparable to internodal cells of Ceramium; corticating cells dividing transversely and covering entire axial cell, forming 1 to many spines at upper portion of each node. Cells uninucleate. Tetrasporangia tetrahedrally divided, in rings at nodes, sometimes on specialized branches. Spermatangia in terminal clusters from tufted, adventitious branchlets, these arising from pericentral cells at nodes. Development of gonimoblast as in Ceramium; mature gonimoblast surrounded by several sterile branches.
Centroceras clavulatum (C. Ag.) Mont.
Ceramium clavulatum C. Agardh 1822b: 2. Centroceras clavulatum (C. Ag.) Montagne 1846a: 140; Smith 1944: 328.
Thalli tufted, dark red, 1-3 cm tall in subtropical and tropical portions of range, 4-5(15) cm tall in northern portion of Pacific Coast range; branching alternate, sometimes almost ternate, each dichotomy of equal length; ultimate branches incurved in pairs; each segment in younger portions with several spines of 1 or 2 cells, the spines not always found in older portions; thalli brittle on drying, easily loosened at nodes; reproductive structures as described for genus.
Locally abundant on sand-swept rocks, midtidal to lower intertidal, throughout Calif. from Santa Cruz to San Diego, and throughout Baja Calif. to Callao, Peru (type locality). Common in most oceans; in the tropics mostly epiphytic or forming parts of turf.
Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.
