Habitat & Distribution
Phyllospadix is distributed from Alaska to Mexico. The plants are rooted (attached) to solid rock. A covering of sediments may obscure this attach-ment. Paul G. Harrison (University of British Columbia) has observed surf-grass roots buried deeper than 50 cm (20 in) in accumulated sediments.
Phyllospadix scouleri and P. serrulatus grow in wave-exposed areas in the lower intertidal and subtidal regions, and in tide pools. Phyllospadix torreyi is found intertidally and subtidally, below P. scouleri, and is frequently found in channels and back eddies, where sand accumulates.
Phyllospadix scouleri (surfgrass) with seed pod.
Green Seaweeds | 49
Green Seaweeds
Green seaweeds are part of a larger group, the green algae (the division Chlorophyta), which inhabit almost every conceivable habitat—soil, snow, air, and inside rock and polar bear hair. There are approximately 6,000 green algal species, most of which are associated with fresh water. The greens are distinct from the brown and red seaweeds by virtue of their pigmentation, the chemical nature of their storage products and cell walls, and ultra-structural details such as chloroplast (cell structure responsible for photosynthesis) and flagella (whip-like appendages for movement). All green plants have similar pigments, with chlorophyll being the dominant form, which accounts for their green colour. The major storage product of most green plants is starch.
The marine green seaweeds of our area are represented by swimming and non-swimming unicellular forms, filaments, sheets, and globular and cushion-like forms. Close to 130 green seaweed species are recognized locally. Here we describe five basic forms and 40 species that represent the diversity found from Alaska to central California. Most included species are distributed through southern California into Mexico as well.
Washed-up Ulva sp. blades cover the beach in Comox, BC.
Pacific Seaweeds
50 | Filaments
Filaments
Filamentous (thread-like) green seaweeds are characterized as being one cell wide and variously branched or unbranched. Some forms may remind the insensitive explorer of scum. Of all the seaweeds, these plants are the most similar to macroscopic freshwater algae. Their general appearance suggests a tight-knit assemblage, but microscopic features distinguish the 35-plus local species into a wide range of diverse green algal groups. They may have one or several nuclei per cell, the filament may be compartmentalized by cross-walls or not (making them essentially unicellular) and they have many types of life cycles. One life cycle incorporates both a filamentous and globular form (Derbesia, p. 57). The following examples express the morphological range of common green filaments.
Unbranched Filaments
Chaetomorpha (green excelsior) p. 51
Rhizoclonium (green fish line) p. 52
Urospora (Hanic’s green barrels) p. 53
A sand-swept patch of Chaetomorpha sp. (individual filaments on fingers).
Green Seaweeds | 51
Identifying Pacific Seaweeds
Branched Filaments
Acrosiphonia (green rope) p. 55
Cladophora (green tuft) p. 56
Derbesia (green sea grape) p. 57
Bryopsis (green sea fern) p. 58
Unbranched Filaments
Chaetomorpha Green excelsior
Class Siphonocladophyceae Order Cladophorales Family Cladophoraceae
Number of Species
Chaetomorpha (Greek=bristle hair) is a complex tangle of species that require investigation; currently, there are eight species listed in our area.
Description
Chaetomorpha grows as a single chain of cylindrical to barrel-shaped cells resembling a string of emerald beads under a good hand lens. The filaments may reach 20 cm (8 in) in length but are typically shorter. Plants may be found
Chaetomorpha sp.
52 | Filaments
Pacific Seaweeds
as tangled masses floating unattached, as clumps of upright filaments, or they may appear as single wayward strands sticking out among other algae.
Habitat & Distribution
Chaetomorpha can be found in tide pools and mud flats in protected to semi-exposed waters in the mid- to lower intertidal region, from Alaska to central California.
Rhizoclonium Green fish line
Above: Rhizoclonium lubricum filaments