Monotypic brown algae genera

Ascophyllum nodosum is a large, common cold water seaweed or brown alga (Phaeophyceae) in the family Fucaceae. Its common names include knotted wrack, egg wrack, feamainn bhuí, rockweed, knotted kelp and Norwegian kelp. It grows only in the northern Atlantic Ocean, along the north-western coast of Europe (from the White Sea to Portugal) including east Greenland and the north-eastern coast of North America. Its range further south of these latitudes is limited by warmer ocean waters. It dominates the intertidal zone. Ascophyllum nodosum has been used numerous times in scientific research and ha

Nereocystis (Greek, 'mermaid's bladder huki kelp') is a monotypic genus of subtidal kelp containing the species Nereocystis luetkeana. Some English names include edible kelp, bull kelp, bullwhip kelp, ribbon kelp, bladder wrack, and variations of these names. Due to the English name, bull kelp can be confused with southern bull kelps, which are found in the Southern Hemisphere. Nereocystis luetkeana forms thick beds on subtidal rocks, and is an important part of kelp forests.

Pelvetia canaliculata, the channelled wrack, is a very common brown alga (Phaeophyceae) found on the rocks of the upper shores of Europe. It is the only species remaining in the monotypic genus Pelvetia. In 1999, the other members of this genus were reclassified as Silvetia due to differences of oogonium structure and of nucleic acid sequences of the rDNA.

Postelsia palmaeformis, also known as the sea palm (not to be confused with the southern sea palm) or palm seaweed, is a species of kelp and classified within brown algae in the SAR supergroup of eukaryotes. It is the only known species in the genus Postelsia. The sea palm is found along the western coast of North America, on rocky shores with constant waves.

Egregia menziesii is a species of kelp known commonly as feather boa kelp. It is the only species in the monotypic genus Egregia. It is native to the coastline of western North America from Alaska to Baja California, where it is a common kelp of the intertidal zone.

Pelagophycus is a monotypic genus of kelp. It is found in deep waters off the west coast of central North America. The species Pelagophycus porra, also known as elk kelp, grows in temperatures of no higher than .

Ascoseira is a monotypic genus of seaweed in the brown algae (class Phaeophyceae). The single and type species, Ascoseira mirabilis Skottsberg, is a large parenchymatous macroalgae, and is endemic to the Antarctic Ocean. Ascoseira is assigned to its own order. The alga grows in subtidal waters at depths of from 3 to 15 meters.