UC specimens and range limits for Cladophora microcladioides

• 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: Ridley Island, Prince Rupert, British Columbia, UBC-A68565; Coos Head, Coos Bay, Oregon, OSC-2786. In California, disjunct to Doran Beach, Sonoma Co.; disjunct to Monterey and Santa Cruz; south to San Diego; mainland Mexico.

Status: There are no records for this poorly known species in GenBank. This species needs re-investigation, especially in light of its range disjunctions and morphological diversity, as do the rest of the west coast species in this genus.

Habitat: Low intertidal to subtidal

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

Search Sequences in GenBank

Illustration from DeCew's Guide to the Seaweeds of British Columbia, Washington, Oregon, and Northern California

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 microcladioides Coll.

Collins 1909b: 17; Smith 1944: 59; Scagel 1966: 92.

Thalli of erect spreading tufts 5-10(20) cm tall, dull to glaucous green; apical cells 35-50 µm diam.; cells in midportions 60-80 µm diam.; basal cells 100-150 µm diam., 1.5-4 times as long throughout; ultimate branches tapering slightly to rounded apices; branching in lower main axes occasionally dichotomous to trichotomous, alternate above, the oldest laterals branched pectinately, the youngest generally simple and progressively shorter toward apex of axis.

Infrequent, saxicolous or on wood or plastic floats, low intertidal, Br. Columbia to Baja Calif. and Gulf of Calif. 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.

Notes: This species can be very small (2 cm) in intertidal southern California but is larger subtidally. There is poor consensus on its identity, reflected in the wide range of morphologies in herbarium specimens.