Division Phaeophyta (Brown algae)   Class Phaeophyceae Order Chordariales Family Chordariaceae Analipus japonicus (thickly leaved rockweed) Found in the upper intertidal area, Annelipis japonicus is frequently found on rocks exposed to moderately heavy surf. This brown alga possesses a thallus that ranges in color from tan to dark brown that supports branches up to 35 cm tall. The axis and branches are solid in lower areas of the plant, and become hollow towards the terminal end of this alga.   Family Ralsiaceae Ralfsia pacifica (tar spot alga) Occurring at all tidal levels, Ralfsia pacifica encrusts its substrate producing well-defined margins that cause it to resemble a tar-like coating. Ranging from tan to brownish-black in color, its outer surface bears concentric rings or ridges. Order Fucales Family Cystoseiraceae Cystoseira osmundacea Easily characterized by its square stipe, this brown alga also possesses midribbed non-serrated blades that lack dichotomous branching patterns. The terminal branches of the thallus are slender and many bear a series of rounded floats. Cystoseira grow up to 8 meters in length and are found in low intertidal zones and kelp beds.   Family Fucaceae Fucus distichus (common rockweed) Commonly referred to as "rockweed", this brown alga is found in the mid-intertidal zone, usually below Pelvetia and barnacles. Its branches are thin and flattened and possess a distinct midrib; small air sacs are located near terminal branches. Fucus attaches to its substrate by means of a holdfast. At low tide, dense growths of this alga cover the rocky substrate and provide a moist habitat for crabs, sea slugs, isopods and sea stars, while hydroids, tube worms, and other organisms attach to the Fucus and feed on the plankton in the water during high tides. Fucus is on the right side of the lower image and a Pelvetiopsis sp. is on the right.   Pelvetia fastigiata (spindle-shaped rockweed) Found in the mid-intertidal zone protected from full surf, this alga forms conspicuous middle intertidal beds. Pelvetia grow from 15 to 40 centimeters tall, and dichotomous branching is observed. Branches are thick and fleshy, but are slender and cylindrical lower on the plant. Pelvetia's blades measure 1 to 2 centimeters across, and air bladders are frequently found in upper portions. Its color may range from tan to brown, and is sometimes slightly tinged with green.   Order Laminariales Family Alariaceae Alaria marginata (long bladed alaria) Characterized by long, smooth, strap-like blades that are centrally ribbed, Alaria marginata are found at the low intertidal zone on exposed rocks (near Postelsia). The plant possesses an axial stipe arising from a holdfast terminating in or bearing distally a single, very prominent blade that is larger than any lateral blades. The blades of Alaria are non-serrated, and no floats are found on this alga.   Egregia menziesii (feather boa kelp) Commonly referred to as the "feather boa" kelp, Egregia menziesii is distinguished by long, flat stipes up to several meters in length bearing hundreds of small blades along the sides. Some of these blades are modified as minute floats. Anchored by means of a holdfast, Egregia is common in rocky intertidal areas. Its color may range from tan to brown, and is sometimes slightly tinged with green.   Pterygophera californica Restricted to the low intertidal zone and below, Pterygophera californica possesses a woody, flattened axial stipe arising from a holdfast bearing lateral blades or branches. The stipe terminates in or bears distally a single prominent blade that lacks a midrib and serrations. No floats are present on this alga. Pterygophera varies in size, but may grow up to 25 meters or more in length.   Family Laminariaceae Laminaria dentigera Lanimaria dentigera are found in the low intertidal zone and are often used as an indicator of the -1 foot tide level. This brown alga possesses an axial stipe arising from a holdfast or prostrate rhizome, and never bears lateral branches or blades. Its single blade at the terminal end of the stipe is non-serrated. Additionally, Laminaria lack floats of any sort.   Family Lessoniaceae Macrocystis integrefolia (small perennial kelp) Commonly known as the giant sea kelp, Macrocystis integrefolia is characterized by a large corrugated blade with serrated edges and a single elongated air bladder at the base of each blade. Found in low intertidal areas, Macrocystis grows up to 20 meters in length and sometimes forms large underwater kelp forests. (more pictures 1)   Postelsia palmaeformis (sea palm) Commonly known as the sea palm, this brown alga is easily recognized by its resemblance to a small palm tree. It possesses an erect and trunk-like stipe bearing a terminal cluster of blades. Postelsia palmaeformis is found at exposed, surf-beaten rocks in the mid-intertidal zone. (more pictures 1)