UC specimens and range limits for Cladophora columbiana

• Blue markers: specimen records
• Yellow marker: type locality, if present
• Red markers: endpoints of range from literature

View map from the Consortium of Pacific Northwest Herbaria

Notes: Northern records: southern Sea Otter Sound, Hecate Island, Alaska, UBC A70121. Southern records: San Diego, Pacific Beach, MICH-684522; south side of Cabo Colnett, NCU-A-0006938. Records from the tropics should be re-investigated.

Status: This species is easily recognized, though variable in form. There are no records for this common species in GenBank.

Habitat: Uppermost to upper intertidal or in pools

Life History: Not investigated, but probably alternation of isomorphic phases, with quadriflagellate zoospores and biflagellate isogametes.

Search Sequences in GenBank

Cladophora Kützing 1843

Thalli sparsely to profusely branched, erect, the upper branches usually conspicuously branching pectinately or unilaterally. Chloroplasts conspicuously reticulate or disklike, containing many pyrenoids. Lower branches dichotomously or many times branched. Lateral branches short, not branching further, or the lower laterals longer than the upper newly formed branches, occasionally branching again. Erect branches not entangled by hooks, but lower portions sometimes matted and difficult to separate because of adventitious rhizoids produced by lower cells and fusing with adjacent cells. Basal portion usually of short creeping rhizoids growing together and making firm mat. Asexual reproduction by quadriflagellate zoospores formed in terminal and subterminal cells of branches; pore of escape of zoospores thought to have some taxonomic utility. Sexual reproduction by biflagellate isogametes.

The species of Cladophora are highly variable with respect to morphology and ecology, as is clearly reflected in the nomenclatural confusion surrounding the taxa. Van den Hoek (1963) performed a herculean task in collecting, culturing, and clarifying the status of the European taxa. It is clear from a critical assessment of his studies that for the most part the application of names of European species to Pacific Coast Cladophora is in error, either because of the existence of earlier homonyms ( e.g. C. sericea) or because as presently understood the West Coast specimens do not fit the newly drawn detailed descriptions (e.g. C. columbiana, previously known as C. trichotoma). Furthermore, the lack of understanding of Western Pacific (Asian) species of Cladophora has led to the exclusion of those taxa from the North American West Coast. Though the following classification is imperfect, it does represent a determined effort to apply correct names to the West Coast species. The lack of large numbers of collections with adequate locality data and the lack of culture studies hamper any effort to be definitive. Nonetheless, we believe that this classification will at least acknowledge the contributions of van den Hoek, as well as those of Sakai (1964) from Japan, and that further studies, so badly needed, will begin with a firmer grounding than if the attempt had not been made.

Cladophora columbiana Coll.

Collins 1903: 226. Cladophora trichotoma sensu Setchell & Gardner 1920b: 210; Smith 1944: 58; Scagel 1966: 93. Not C. trichotoma (C. Agardh) Kützing (= C. pellucida (Hudson) Kütz., see van den Hoek 1963: 215). C. hemisphaerica Gardner 1918: 83; Smith 1944: 57.

Thalli bright green, in low matted tufts, 3-5(15) cm tall, 2-4(20) cm diam.; apical cells 90-150(170) µm diam., including lateral walls of 23.4-26 µm; cells of main axes 200-250 µm diam., 5-10 times as long; cells cylindrical; filaments unbranched or branched in various ways, the base a single, only slightly modified cell; or rhizoidal base giving rise to low, horizontally directed branches bearing on their upper surfaces rows of short, irregularly branched, erect filaments; or basal rhizoids mingled and occasionally fusing with adventitious rhizoids from lower cells of erect filaments.

Frequent to locally abundant, saxicolous, midtidal to low intertidal, Vancouver I., Br. Columbia (type locality), to Baja Calif. and Gulf of Calif.

This is the most abundant and characteristic species of Cladophora on the Pacific Coast. The common form grows on rocks, and as Smith (1944) has pointed out, sand accumulates between the branches. The less common form (= C. hemisphaerica), which makes very large loose tufts, grows in tidepools; the structure of the basal portions, the branching habit, and the sizes of the filaments are, however, extremely similar to those of the rock-dwelling form.

Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.