- Blue markers: specimen records
- Yellow marker: type locality, if present
- Red markers: endpoints of range from literature
Rhodymenia Greville 1830
Thalli erect or spreading, 2-40 cm tall, usually stipitate from discoid holdfasts, with or without cylindrical stolons; branches firm, bladelike, usually dichotomously or irregularly divided; axial branching sometimes sympodial; medulla of large isodiametric cells grading outwardly to smallcelled cortex of 2 or 3 cell layers. Tetrasporangia cruciately divided, scattered over entire blade or branch, or in subterminal or terminal sori, sometimes on small marginal or subterminal bladelets, embedded beneath little-modified cortex or in nemathecia. Spermatangia in small superficial sori; carpogonial branches 3- or 4-celled; base of carposporophyte with small fusion cell; cystocarps prominent, scattered or restricted to branch apices, with thick ostiolate pericarp.
Rhodymenia californica Kyl.
Kylin 1931: 21; Dawson 1941: 135; Smith 1944: 301.
Thalli bushy, clumped, 1 to many erect or spreading blades dichotomously or flabellately branched on short stipes arising from basal disks, early producing irregular horizontal subcylindrical stolons; medulla of 2 or 3 cell layers grading abruptly through 2 or 3 cortical layers of smaller cells; tetrasporangia on 1 or both sides of blades, in rounded, terminal, usually nemathecial sori; spermatangia in superficial sori, covering terminal blades; cystocarps scarcely rostrate, usually aggregated on terminal divisions.
Rhodymenia californica var. californica
Thalli in fan-shaped clumps, spreading by several horizontal stolons arising from stipes; blades 2-5 times dichotomously divided, rigid, narrowly linear, 2.5-7(11) cm tall, 1.5-3 mm broad, 70-150 µm thick; terminal divisions blunt to pointed.
On shaded rocks, lower intertidal to subtidal, S. Br. Columbia to Nayarit, Mexico; frequent to common throughout Calif. Type locality: Pacific Grove, Calif.
Rhodymenia californica var. attenuata (Daws.) Daws.
Rhodymenia attenuata Dawson 1941: 139. R. californica var. attenuata (Daws.) Daws. 1963a: 459.
Thalli as for the species, but with the terminal divisions 1.5-2 times longer, the apices attenuate, the lower branching at longer intervals and more lax.
Occasional on rocks throughout range of species, characteristically in deeper water. Type locality: San Pedro, 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.
